JPH1099855A - Ultrapure water supply plant equipped with ultrafiltration function and supply of ultrapure water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrapure water supply plant extremely high in the purity of output water from a terminal, capable of supplying stable ultrapure water and enabling adjusting work high in productivity at re-operation and an ultrapure water supply method. SOLUTION: This ultrapure water supply plant 1 consists of an ultrapure water making apparatus 2 and the piping system 3 connected to the secondary side of the ultrapure water making apparatus 2 to carry formed ultrapure water to a semiconductor washing process 8. In this case, an ultrafiltration treatment apparatus 4 is connected and arranged to the terminal or most downstream part of the piping system 3 and the ultrapure water passed through the piping system 3 to reach the terminal is subjected to ultrafiltration treatment by the ultrafiltration apparatus 4 and ultrapure water 5 after ultrafiltration treatment is supplied to a semiconductor washing process 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrapure water supply plant having an ultrafiltration function, and more particularly to an ultrapure water supply plant which is used in a semiconductor manufacturing process and has an ultrafiltration function and has been subjected to an ultrafiltration treatment. The present invention relates to an ultrapure water supply plant that supplies ultrapure water to a semiconductor cleaning process.

[0002]

2. Description of the Related Art In a semiconductor manufacturing process, a process of cleaning a semiconductor wafer in process by running water is indispensable. However, in such running water cleaning, the purity of a semiconductor wafer is reduced in order to avoid reverse contamination due to adhesion of fine particles and the like contained in the cleaning water. Of pure water is used. Conventionally, such pure water is configured to be supplied to a semiconductor cleaning process from a pure water supply plant, which is referred to as a point of use (utility facility) and provided with a pure water generation device and the like.

FIG. 6 shows a process flow sheet of such a conventional pure water supply plant. In the figure, a pure water supply plant 100 includes an ultrapure water generator 2, a piping system 3 for guiding the generated ultrapure water to a downstream side of a use point, and a microfiltration filter 104 connected to an end of the piping system 3. It is composed of Alternatively, the microfiltration filter 104
Is applied.

[0004] The ultrapure water generator 2 is a reverse osmosis membrane (RO membrane).
Osmosis membrane unit 21 comprising an ultrafiltration membrane (UF membrane: ultrafiltration membrane) mainly separating and purifying colloidal substances contained in the generated ultrapure water (Ultrafiltration module: hereinafter referred to as UF module)
Consists of 22.

[0005] The UF module has, for example, a particle-removing performance of 0.3.
It is a unit having a function of 01 μm or more, and a microfiltration filter having a function of, for example, 0.5 μm or more in particle removal performance is applied.

The operation of the pure water supply plant 100 will be described. First, the raw water 10 is pressurized to a predetermined high pressure and introduced into the reverse osmosis membrane unit 21, where pure water generated by the reverse osmosis action of the reverse osmosis membrane is used. Output to the next side. This pure water is UF
The contained colloidal substance and the like are separated and removed by the module 22 and sent out from the ultrapure water generator 2 as ultrapure water.

[0007] The ultrapure water is introduced into the piping system 3 and moves through the piping system 3. Here, for example, chips generated during cutting of the piping due to piping work performed on the way may be mixed into the ultrapure water. If there is, such contaminants are captured and removed by the microfiltration filter 104 connected to the end of the piping system 3. In this way, the pure water 105 from which impurities have been removed is supplied from the pure water supply plant 100 to the semiconductor cleaning step 8.

[0008]

However, in the above-described conventional configuration, when the operation is temporarily stopped due to a factory leave or the like, the attached microfiltration filter 104 is installed.
However, there is a problem that water is interrupted and water accumulates inside, and bacteria grow in this water.

In general, bacteria have an average diameter of about 0.01 μm to 0.05 μm (100 to 500 angstroms) for small viruses, or about 0.1 μm for influenza viruses, Pseudomonas aeruginosa and dysentery. Bacteria have an average diameter of about 0.1 μm to 0.5 μm, and E. coli have an average diameter of about 1 μm.

Therefore, when such bacteria are generated in the microfiltration filter 104, the bacteria mixed in the initial water flow when the plant is restarted pass through the microfiltration filter 104, and the pure water containing the bacteria is washed. There is a disadvantage that the water is supplied to the semiconductor cleaning process as water.

Further, injection of a disinfectant or a disinfectant to avoid the generation of bacteria requires a long water flow time (lead time) for complete removal of such chemicals at the time of restart, and furthermore, bacteria are generated. In this case, the sterilized residue (corpse) adheres to the membrane or the like, and gradually peels off and separates during long-time use, and enters the output water.

Furthermore, the generation of bacteria mainly occurring during the shutdown of the plant is caused not only by the microfiltration filter but also by, for example, the piping system 3, various valves and instruments connected to the piping system 3, and liquid retention in the orifice. There is a possibility that this may also occur in a part or the like, and any of these causes a negative cause of lowering the purity of the output water.

As described above, in the conventional pure water supply plant, despite the provision of a high-performance ultrapure water generator, the ultrapure water of extremely high purity can be stably provided due to a problem in the downstream portion thereof. However, there is a problem in that the output is low, so that the plant remains in a pure water supply plant having lower purity and stability.

[0014] In addition, as described above, each part of the plant is configured to avoid contact with the external atmosphere as much as possible for the purpose of avoiding the generation of bacteria. There is also a drawback that the venting treatment becomes inefficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems and disadvantages of the prior art, and an object of the present invention is to provide a very high purity of output water from a terminal and a stable supply of ultrapure water. It is another object of the present invention to provide an ultrapure water supply plant and an ultrapure water supply method capable of performing an adjustment operation with high productivity at the time of restart.

[0016]

In order to solve the above-mentioned problems, an ultrapure water supply plant according to the present invention is connected to an ultrapure water generation device and a secondary side of the ultrapure water generation device, and is configured to generate the ultrapure water. In the ultrapure water supply plant consisting of a piping system that carries the ultrapure water to the semiconductor cleaning step, an ultrafiltration device is connected and installed at the end or the most downstream portion of the piping system, and passes through the piping system and ends. Is subjected to ultrafiltration by the ultrafiltration device, and the ultrapure water after the ultrafiltration is supplied to the semiconductor cleaning step.

According to the above configuration, the output water is subjected to the ultrafiltration at the very end, that is, at the most downstream, so that the contamination and the particulates generated upstream of the ultrapure water supply plant are captured at the very end. Thus, ultrapure water of extremely high purity is supplied.

Alternatively, when the ultrapure water supply plant according to the present invention has a configuration in which an air bleeding means is provided in the secondary pipe portion of the ultrafiltration device, the maintenance work and the exchange work of the ultrafiltration membrane are performed. When the plant is restarted later, the air and gas remaining in the device are quickly removed by the air bleeding means. As a result, the productivity of the adjustment work at the time of restarting the plant is improved,
An early launch is done.

Alternatively, when the ultrapure water supply plant according to the present invention has a configuration in which a liquid discharge flow path that can be opened and closed is provided in the secondary pipe section of the ultrafiltration apparatus, By-pass drainage of the initial water flow generated at the time of re-starting after a temporary stop is performed, thereby preventing the unstable initial water flow from flowing into the cleaning process, and enabling a smooth transition to a stable steady state. .

Alternatively, the ultrafiltration apparatus of the ultrapure water supply plant according to the present invention is constituted by a plurality of ultrafiltration apparatuses each having a primary side and a secondary side connected in parallel,
If the number of the ultrafiltration devices connected in parallel is configured to be freely expandable or decrementable according to the required amount of ultrapure water, the scale of the ultrapure water supply plant may be reduced in the semiconductor cleaning process. It is easy to adjust the scale to the optimum for the capacity, thereby realizing a cost-effective and flexible plant.

Alternatively, the ultrapure water supply plant according to the present invention includes a plurality of ultrafiltration devices, and connects each primary side of the plurality of ultrafiltration devices in parallel to an end of the piping system, And when each secondary side is configured to be supplied at least independently to each of the semiconductor cleaning processes of a plurality of systems, the management of each semiconductor cleaning process is facilitated, and the other ultrafiltration device is operated while being operated. Maintenance becomes possible, and management costs can be reduced.

[0022] In the method for supplying ultrapure water according to the present invention, the ultrapure water generated by the ultrapure water generator is conveyed to a supply point via a piping system, and then to an ultrafiltration device connected to the end of the piping system. After the ultrafiltration process, the semiconductor device is supplied to a semiconductor cleaning step.

According to the ultrapure water supply method having the above-described structure, impurities and the like mixed in the liquid while moving through the piping system are effectively removed at the most downstream side, so that the ultrapure water supplied to the semiconductor cleaning step is removed. It is possible to increase the purity in water and improve the yield of the semiconductor manufacturing process.

[0024]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a process flow sheet of one embodiment of an ultrapure water supply plant according to the present invention. As shown in FIG. 1, an ultrapure water supply plant 1 according to the present invention is connected to an ultrapure water generator 2 that generates ultrapure water from raw water 10 and a secondary side of the ultrapure water generator 2. hand,
The ultrapure water that is connected and installed at the piping system 3 that carries the generated ultrapure water to the end of the plant and the ultrapure water flowing from the piping system 3 at the end (or the most downstream part) of the piping system 3 It comprises an ultrafiltration device 4 for supplying pure water 5 to a semiconductor cleaning step 8.

The ultrapure water generator 2 is a reverse osmosis membrane (RO membrane)
And an ultrafiltration module 22 composed of an ultrafiltration membrane mainly for separating and purifying colloidal substances contained in the generated ultrapure water. Further, the ultrafiltration device 4 includes an ultrafiltration membrane (UF)
Film).

The operation of the ultrapure water supply plant 1 will be described. The raw water 10 is pressurized to a predetermined high pressure and introduced into the reverse osmosis membrane unit 21, and pure water is output to the secondary side by the reverse osmosis effect of the reverse osmosis membrane. This pure water is supplied to the ultrafiltration module 2
2 separates and removes colloidal substances and the like, and is sent out from the ultrapure water generator 2 as ultrapure water.

The ultrapure water is introduced into the piping system 3 and moves through the piping system 3. At this time, the fine particles adhering to the inner wall of the piping system 3 separate from the inner wall and enter the ultrapure water. Even if such a situation occurs, such impurities other than water molecules are reliably captured and removed by the ultrafiltration membrane (UF membrane) of the ultrafiltration device 4 connected and installed at the end of the piping system 3. You. Thus, the ultrapure water 5 from which impurities have been removed is always supplied to the semiconductor cleaning step 8.

As described above, in the present invention, an ultrafiltration (UF) module mainly used for purifying ultrapure water by separating and removing colloidal substances when producing ultrapure water used in the semiconductor cleaning step. At the point of use, it is possible to improve the yield in manufacturing CCD devices, including the yield in, for example, gate oxide film breakdown voltage processing.

FIG. 2 is a process flow sheet showing the configuration of an embodiment of the ultrafiltration apparatus described above. In the figure,
The ultrafiltration device 41 includes three ultrafiltration devices 42A to 42C each having a primary side and a secondary side connected in parallel. The pure water 3a flowing from the piping system 3 is pressurized to an ultrafiltration pressure by means (not shown), supplied to all three ultrafiltration devices 42A to 42C, and subjected to ultrafiltration processing in each device. Is made.

Here, the number of ultrafiltration devices connected in parallel (three in this example) can be increased or decreased depending on the required amount of ultrapure water. In the configuration shown in FIG. 2, ultrapure water 43 is supplied to the cleaning step in an amount obtained by summing up the processing amounts of the three ultrafiltration devices 42A to 42C. If a larger flow rate is required, more ultrafiltration devices may be additionally connected in parallel.

In order to eliminate the accumulation of air at the time of initial water flow, an air release valve 4
4 is provided as air bleeding means. In addition, in order to simplify the pure water treatment at the time of filter replacement and air bleeding, a liquid discharge passage 45 that can be opened and closed is provided on the secondary side of the ultrafiltration device 41.
And a drain pan 46 are provided so that drainage is always possible.

With the above-described structure, the air bleeding operation after the maintenance is completed can be easily and quickly performed only by operating the air bleed valve 44. As a result, the air remaining in the apparatus is effectively discharged. Removed.

In addition, the initial drainage water having an unstable purity and immediately after the restart can be easily and quickly bypassed and drained only by operating the liquid discharge passage 45, so that the adjusting operation until the supply of the stable output water is performed. Simplified and improved productivity.

FIG. 3 is a process flow sheet showing the configuration of another embodiment of the ultrafiltration device. In the drawing, the ultrafiltration device 51 includes three ultrafiltration devices 52A, 52B, 5
2C, each primary side of these ultrafiltration devices is connected in parallel to the end of the piping system, and pure water 3a flowing from the piping system 3 is pressurized to ultrafiltration pressure by means not shown,
It is supplied to all three ultrafiltration devices 52A to 52C, and ultrafiltration is performed in each device.

The secondary sides of the ultrafiltration devices 52A to 52C are:
Ultrapure water is supplied individually to each of the three systems of semiconductor cleaning processes 60A to 60C. For example, the secondary side 53a of the ultrafiltration device 52A is connected to the semiconductor cleaning step 60A and supplies ultrapure water exclusively for the semiconductor cleaning step 60A. Similarly, the secondary side 53b of the ultrafiltration device 52B is connected to the semiconductor cleaning step 60B,
Ultrapure water is supplied exclusively for B, and the secondary side 53c of the ultrafiltration device 52C is connected to the semiconductor cleaning step 60C to supply ultrapure water exclusively for the semiconductor cleaning step 60C.

Each of the secondary sides 53a-53c has an air vent valve 54A-54C and an openable / closable liquid discharge passage 55.
A to 55C are connected to drain pans 56A to 56C, respectively.

According to this configuration, the control of the ultrapure water supply side in each semiconductor cleaning process is facilitated, maintenance can be performed while other ultrafiltration devices are operated, and the management cost can be reduced. it can.

In each of the above embodiments, it is effective to provide a pressure gauge on either the primary side or the secondary side or on both sides for the purpose of managing the clogged state of the UF module.

It is preferable that the secondary piping of the UF module is formed as short as possible. That is, a configuration is preferable in which the piping system is extended to a position very close to the semiconductor cleaning step, and the UF module is installed at the end.

As described above, according to the present invention, by providing the UF module at the most downstream side of the ultrapure water supply plant, for example, impurities mixed in the liquid while moving in the piping system or granular formation formed in the middle of the process. Goods can be effectively captured and removed on the most downstream side, thus reducing the number of contaminations and particles in ultrapure water supplied to the semiconductor cleaning process, and improving the yield in the semiconductor manufacturing process. Things.

This effect is shown in the transition graph of dust in liquid in FIG. As is clear from the figure, by applying the ultrapure water supply plant according to the present invention, the number of dust particles in the liquid was significantly reduced as compared with the case of the related art.

As a result, the defect occurrence rate at the time of cleaning the semiconductor device using the ultrapure water supplied from the ultrapure water supply plant according to the present invention is reduced from the conventional 22% in terms of the gate oxide film breakdown voltage shown in FIG. It has been significantly improved to the current level of 0%, thus making it possible to achieve a stabilized and high level of yield.

In the above embodiment, an example is shown in which the present invention is applied to the step of using ultrapure water as washing water or running water.
The present invention is not limited to this, and can be effectively applied to ultrapure water when a mixed solution of ultrapure water and a chemical solution is used for cleaning water.

[0044]

The ultrapure water supply plant according to claim 1 of the present invention is limited to the end of a piping system which is connected to the secondary side of the ultrapure water generator and carries ultrapure water to the semiconductor cleaning step. An external filtration device is connected and installed, ultrapure water reaching the end of the piping system is subjected to ultrafiltration treatment, and the treated ultrapure water is supplied to the semiconductor cleaning process. By being provided at the most downstream side of the ultrapure water supply plant, for example, impurities mixed in the liquid while moving the piping system can be effectively captured and removed at the most downstream side, and thus supplied to the semiconductor cleaning process The yield of the semiconductor manufacturing process can be improved by reducing the number of contamination components and granular components in ultrapure water and performing stable supply of ultrapure water.

Since the ultrapure water supply plant according to the second aspect of the present invention has a structure in which the secondary piping of the ultrafiltration device is provided with an air bleeding means, maintenance work and replacement of the ultrafiltration membrane are performed. When the plant is restarted after the operation, the air and gas remaining in the equipment can be effectively and quickly removed by the air bleeding device, thereby enabling highly productive adjustment work when the plant is restarted. To enable early startup.

The ultrapure water supply plant according to claim 3 of the present invention has a structure in which a liquid discharge flow path that can be opened and closed is provided in the secondary side piping section of the ultrafiltration device, so that the ultrapure water flow is provided. After the water is once stopped, it can be drained by bypassing the initial moisture generated at the time of re-starting, thus preventing unstable initial moisture from flowing into the cleaning process, and after reaching a steady state. The supply to the cleaning step can be started. Moreover, this has the effect of improving the productivity of the adjustment work at the time of restarting the plant and enabling early startup.

In the ultrapure water supply plant according to claim 4 of the present invention, the ultrafiltration device comprises a plurality of ultrafiltration devices,
The primary and secondary sides of these ultrafiltration devices are connected in parallel, respectively, and the number of ultrafiltration devices connected in parallel can be freely increased or decreased according to the amount of ultrapure water required. Because of the reduction, it is easy to adjust the scale of the ultrapure water supply plant to the optimum size for the processing capacity of the semiconductor cleaning process, thereby realizing a cost-effective and highly flexible plant. be able to.

In the ultrapure water supply plant according to claim 5 of the present invention, each primary side of the plurality of ultrafiltration devices is connected in parallel to the end of the piping system, and each secondary side is at least independently provided.
Since the system is configured to be individually supplied to each of the semiconductor cleaning processes of a plurality of systems, management of each semiconductor cleaning process is facilitated, and maintenance can be performed while other ultrafiltration devices are operating. This has the effect of reducing management costs.

In the method for supplying ultrapure water according to claim 6 of the present invention, the ultrapure water generated by the ultrapure water generator is transported to a supply point via a piping system and then connected to the end of the piping system. After being subjected to ultrafiltration treatment by an external filtration device, it is configured to be supplied to the semiconductor cleaning process. For example, impurities mixed in the liquid while moving in the piping system can be effectively reduced at the most downstream side. Therefore, impurities in ultrapure water supplied to the semiconductor cleaning process can be reduced, and the yield of the semiconductor manufacturing process can be improved.

[Brief description of the drawings]

FIG. 1 is a process flow sheet of an embodiment of an ultrapure water supply plant according to the present invention.

FIG. 2 is a process flow sheet showing an example of the configuration of the ultrafiltration device.

FIG. 3 is a process flow sheet showing another configuration example of the ultrafiltration device.

FIG. 4 is a graph showing an effect of capturing dust in liquid by the ultrapure water supply plant according to the present invention.

FIG. 5 is a diagram showing a change in gate oxide film breakdown voltage yield due to introduction of a UF module.

FIG. 6 is a process flow sheet of a conventional ultrapure water supply plant.

[Explanation of symbols]

1 ... ultrapure water supply plant, 2 ... ultrapure water generator, 3
... Piping system, 4 ... Ultrafiltration device, 5 ... Ultra pure water, 8
... semiconductor cleaning process, 10 ... raw water, 21 ... reverse osmosis membrane unit, 22 ... ultrafiltration module.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/304 341 H01L 21/304 341Z

Claims (6)

[Claims] 1. An ultrapure water supply plant comprising an ultrapure water generator and a piping system connected to a secondary side of the ultrapure water generator and transporting the generated ultrapure water to a semiconductor cleaning step. An ultrafiltration device is connected and installed at the end or the most downstream portion of the piping system, and ultrapure water passing through the piping system and reaching the end is subjected to ultrafiltration by the ultrafiltration device. An ultrapure water supply plant, characterized in that ultrapure water after external filtration is supplied to a semiconductor cleaning step. 2. The ultrapure water supply plant according to claim 1, wherein an air venting means is provided on a secondary side of the ultrafiltration apparatus according to claim 1. 3. The ultrapure water supply plant according to claim 1, wherein a liquid discharge flow path that can be opened and closed is provided on the secondary side of the ultrafiltration device according to claim 1. 4. The ultrafiltration device comprises a plurality of ultrafiltration devices each having a primary side and a secondary side connected in parallel, and the number of the ultrafiltration devices connected in parallel is required. 2. The ultrapure water supply plant according to claim 1, wherein the ultrapure water supply plant is configured to be freely added or decremented according to the amount of the ultrapure water to be performed. 5. A plurality of ultrafiltration devices, wherein each primary side of said plurality of ultrafiltration devices is connected in parallel to an end of said piping system, and each secondary side is at least independently ultrapure water. 2. The ultrapure water supply plant according to claim 1, wherein each of the plurality of systems is individually supplied to each of the semiconductor cleaning processes. 6. The ultrapure water generated by the ultrapure water generator is transported to a supply point via a piping system, and then subjected to ultrafiltration by an ultrafiltration device connected to an end of the piping system, and then to a semiconductor. A method of supplying ultrapure water, wherein the method supplies the ultrapure water to a cleaning step.