JP2001044089A - Clean room system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a clean room system that achieves prevention of obstruction caused by the adhesion of gaseous contaminants and water to a product, and at the same time, the prevention of obstruction caused by static electricity in an electronic device product or the like. SOLUTION: In this clean room system, a wafer-manufacturing device 7 and a handling chamber 4 adjacent each other are arranged in an existing clean room 100, a clean air-supplying device 2, for eliminating contaminants and at the same time for supplying clean air with low dew point, is connected to the handling chamber 4 via a supply duct 5, and the inside of the handling chamber 4 is equipped with a handling arm 11 for handling a semiconductor wafer, a soft X-ray, irradiating device 3 for electrically neutralizing electrification of the semiconductor wafer on the handling arm, and differential pressure exhaust vent 6 for interlocking the clean air-supplying device 2 for discharging the clean air to the outside from clean space 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a clean room system for constructing a clean space having a high degree of cleanliness, and more particularly to a clean room system suitable for constructing a manufacturing space and a product transport space in the semiconductor industry.

[0002]

2. Description of the Related Art In the recent electronics industry in the production of semiconductors and liquid crystals, as the performance of products such as electronic device products has increased, contamination of products by gaseous contaminants and static electricity damage due to generation of static electricity have been increasing. This is a major cause of lower product reliability and lower yield. Contamination of a product by gaseous contaminants causes a change in electrical characteristics of the product, a modification of the material, and the like. The static electricity damage causes insulation breakdown of a manufactured product, disconnection of a circuit, malfunction of a manufacturing apparatus, and the like.

[0003] As means for preventing the contamination of manufactured products by gaseous contaminants, dry removal means for trapping gaseous contaminants from the air by a filter device or an adsorbent, or gaseous contaminants by water spray are removed. There are known a wet removal means (air washer device) and a gas introduction means for introducing a clean nitrogen gas (or an inert gas) with reduced gaseous pollutants into a clean space.

[0004] As a filter device in the dry removal means, a chemical filter for trapping a specific gaseous pollutant is known. As a clean room structure using a chemical filter, for example, a clean space formed by being separated from the surroundings by a chamber box or the like, and a filter that collects contaminants such as gaseous contaminants in the air and creates clean air. And a purified air supply system (Japanese Patent Application Laid-Open No. H10-340874) including a device and a clean air circulation passage for feeding air from the filter device to the clean space and returning air from the clean space to the filter device. Japanese Unexamined Patent Publication No. 11-44442) is known.
Note that Japanese Patent Application Laid-Open No. H10-340874 describes that the above-mentioned gas introducing means is further provided.

[0005] As for the collection of gaseous pollutants by the adsorbent in the dry removal means, TSA (Thermal Swing Absorption) is used in which outside air is passed through an adsorbent such as silica or alumina at room temperature and the adsorbent is regenerated at a high temperature. A method and a dry dehumidifier (JP-A-11-523) are known. These methods and apparatuses are used as a means for obtaining air with a low dew point by adsorbing and collecting moisture in the air.However, when adsorbing moisture, acid gas or alkaline gas is used.
Water-soluble gaseous pollutants and highly polar organic compounds are also adsorbed and trapped, so that they also function as a means for removing gaseous pollutants.

As means for preventing static electricity failure, for example,
Ionize gas molecules (nitrogen and oxygen in the case of air)
An ion generator is known which electrically neutralizes a charged material in a clean space by ions and electrons generated at this time, or gas molecules or the like which take on one of the charges by being combined with them. Examples of the ion generator include an ion generator using corona discharge by applying an AC high voltage (Japanese Patent No. 2541857) and a neutralizing device for a charged object using electrons generated by the photoelectric effect (Japanese Patent No. 2838900). And a neutralizing structure for a charged object in which soft X-rays having a wavelength of 1 to several hundred angstroms are directly irradiated to the atmosphere around the charged object (Japanese Patent No. 2749202).

[0007]

As a countermeasure against contamination by gaseous contaminants and electrostatic damage, conventionally, a method has been adopted in which individual measures are taken using the means exemplified above. However, there are various problems in the individual correspondence, and there is still room for improvement in preventing a reduction in the yield and reliability of the manufactured product. The problems with the conventional individual correspondence will be described below for each case.

[0008] In the case of taking measures against static electricity without taking measures against gaseous pollutants, in addition to not only contaminating the product with the gaseous pollutants, but also the ions generated by the countermeasures against static electricity are combined with the gaseous pollutants. It becomes gaseous pollutant ions. The gaseous pollutant ions are electrically attracted to a charged material (manufactured product) in the clean space and easily adhere to the charged charge depending on the charge of the gas itself. Therefore, in the case where the countermeasures against static electricity are performed without taking the countermeasures against gaseous pollutants, chemical contamination of manufactured products due to gaseous pollutants and the like is promoted.

In the case of taking measures against gaseous pollutants and measures against static electricity without removing moisture in the air, water molecules floating in the air combine with positive ions generated by the measures against static electricity to become hydronium ions. . This hydronium ion has a positive charge and is easily attracted to a charged material and easily adheres thereto. The adhesion of the water molecules converted into hydronium ions to the charged material (manufactured product) accelerates the growth and corrosion of a natural oxide film on the surface of the manufactured product, and forms a thicker water film.
This water film may serve as a medium for forming a salt when, for example, an acidic gas and an alkaline gas are generated in a clean space, and the formed salt causes particle contamination similarly to dust.

In the case of removing moisture in the air and taking countermeasures against static electricity, the problem caused by the adhesion of water (the adhesion of hydronium ions) hardly occurs, and much of the acidic gas and alkaline gas are reduced. Therefore, the problem of particle contamination hardly occurs. However, a large amount of non-water-soluble organic compounds (for example, low-polarity hydrocarbons) remain, and if countermeasures against static electricity are carried out in the presence of such organic compounds, the organic compounds are likely to be positively charged. It easily adheres to products (manufactured products) and promotes organic contamination of manufactured products.

To summarize the above, the conventional individual countermeasures have the disadvantage of promoting the adhesion of gaseous pollutants to charged materials (manufactured products). In other words, when comparing the case where the countermeasure against static electricity is performed and the case where the countermeasure is not performed, it is suggested that the attachment of gaseous pollutants to the charged material is more likely to occur when the countermeasure against static electricity is performed. This is because gaseous pollutants are much easier to ionize than air (nitrogen molecules and oxygen molecules). Therefore, in order to improve the above drawbacks, it is necessary to take the above-mentioned measures against static electricity in air (clean air) in which gaseous pollutants are reduced and the dew point is low. It is necessary to make the allowable level of water and moisture in the clean space lower than the conventional allowable level.

Also, in consideration of the accelerating progress in the electronics industry, such as high integration and high performance of integrated circuits, contamination of manufactured products by gaseous pollutants, changes in electrical characteristics of manufactured products due to static electricity, dielectric breakdown, etc. It is feared that this problem will become more apparent in the future.

The present invention has been made in view of the above matters,
An object of the present invention is to provide a clean space capable of simultaneously preventing gas-based contaminants and moisture from adhering to manufactured products and preventing electrostatic damage in manufacturing electronic device products and the like.

[0014]

SUMMARY OF THE INVENTION The present invention is a clean room system, and has the following structure as means for solving the above-mentioned problems. That is, the clean room system according to the present invention includes a clean gas supply unit that supplies a clean space having a low dew point and a clean gas from which contaminants including dust and gaseous contaminants are removed, and electrically charges a charged material in the clean space. And a static eliminator for summing.

According to the above construction, gaseous pollutants and water molecules, or ions thereof, which are electrically attracted to and adhere to a charged object typified by working equipment or manufactured goods in the clean space, are cleaned. There is almost no presence in the space, and since the charged material in the clean space is electrically neutralized by the static elimination means, gaseous pollutants adhere to the charged material,
The failure due to the adhesion of moisture and the static electricity failure are prevented at the same time.

Further, when the concentration of the contaminants in the clean gas is 1 ppb or less and the dew point of the clean gas is -20 ° C. or less, the clean gas in the clean room system of the present invention adheres to the charged material as the charge is removed. It is preferable to prevent the charged substance from being contaminated by gaseous contaminants, water molecules, or ions thereof. The clean gas in the present invention is not particularly limited as long as the contaminants are removed and the gas is in a clean and dry state with a low dew point and does not adversely affect the contents of work in the clean space. In addition to air, an inert gas such as nitrogen or argon can be exemplified.

The static elimination means in the clean room system of the present invention may be any means as long as it electrically neutralizes the charged material. However, if the ion generator is an ion generator for ionizing clean gas, it does not contact the charged material. This is preferable because the electric neutralization is possible. The ionization of the clean gas by the ion generator may be performed in the clean space or may be performed before the clean gas is introduced into the clean space. Further, if the ion generator is a soft X-ray irradiator that irradiates soft X-rays having a wavelength range of 1 to 100 angstroms to a clean gas, the energy of the electromagnetic waves to be irradiated is strong, so that ozone having a strong oxidizing power is generated. This is preferable because the electrical neutralization in the clean space can be quickly performed.

Further, the clean room system of the present invention comprises:
It is preferable to provide a temperature control means for controlling the clean space to a predetermined temperature, since a modification of a manufactured product (semiconductor wafer or the like) due to an operation in the clean space is prevented. Examples of the temperature control unit include a cooling device that cancels out heat generated by work in the clean space.

Further, the clean room system of the present invention comprises:
It is preferable to provide a clean gas filtering means for collecting dust generated in the clean space, to collect dust generated during operation in the clean space and to prevent particle contamination in the clean space. The adhesion of dust to the surface of an object is governed by sedimentation due to gravity, floating due to buoyancy, electrostatic force (electric attraction), and the like.
It is known that the adhesion of dust to the surface of an object is governed by electrostatic force. Therefore, it is preferable that the clean gas filtering means is capable of collecting dust having a small particle diameter, such as a HEPA filter (High Efficiency particulate Air-filter) or a UPA filter.
LPA filter (Ultra Low Penetration Air-filter)
And the like.

Further, the clean room system of the present invention comprises:
It is preferable to provide a clean gas exhaust unit that exhausts the clean gas from the inside of the clean space to the outside, even if a large amount of contaminants is generated in the clean space, the clean space is quickly returned to the clean state. Further, it is more preferable that the clean gas exhaust means be linked with the clean gas supply means because the number of times of ventilation of the clean space suitable for the work content in the clean space is secured. The number of times of ventilation is a value obtained by dividing the amount of supply or exhaust of clean gas per hour for ventilation by the volume of the clean space. When the clean space is airtight to the outside, the pressure in the clean space can be freely adjusted by interlocking the clean gas supply means and the clean gas exhaust means.

Further, the clean room system of the present invention comprises:
It is preferable to provide a return duct for returning a part of the clean gas in the clean space to the clean gas supply means, because the cost for producing and supplying the clean gas is further reduced.

The above-mentioned contaminant is a concept including a substance or an object which has an adverse effect on the work content in a clean space, and is a particulate contaminant such as dust, an acid gas, an alkaline gas, an organic gas, an inorganic gas, or any of these gaseous substances. It indicates gaseous pollutants including ions and the like. Since the type of pollutant is determined by the work content in the clean space, the contaminant to be removed may be set according to the work content in the clean space.

The dew point is the temperature at which the water contained in the gas appears as water droplets on the surface of the object when the gas is cooled, and indicates how much the water in the clean gas has been removed. It is an indicator. Clean gas is-
It is sufficient that moisture is removed to the extent that a dew point of 20 ° C. or less is exhibited, but it is more preferable that moisture is removed to a lower dew point, for example, a dew point of −100 ° C. or less.

The clean gas supply means may be any means capable of removing moisture and contaminants contained in the gas from the gas, and can simultaneously perform dehumidification of the gas and removal of the contaminants. It may be a means that is used in combination with a dehumidifying means for gas and a means for removing contaminants.

The clean gas supply means capable of simultaneously performing the dehumidification of the gas and the removal of the contaminants is an apparatus for storing the adsorbent and passing the gas through a rotatable rotor to dehumidify the gas. The gas passage area located at the end face of the rotor is divided into a dehumidification area, a regeneration area, and a purge area, and the purge area is located before the transition from the regeneration area to the dehumidification area by rotation of the rotor. As described above, in the dry dehumidifier in which each of the sections is arranged, the ratio of the area of the dehumidified section located on the end face side of the rotor to the area of the other section is 3: 1. JP-A-11-523) can be used. The adsorbent is preferably a metal silicate composed of silicon dioxide and a metal oxide, and the metal of the metal oxide may be determined depending on the type of gaseous pollutant to be removed, such as aluminum or zinc. can do.

[0026]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a clean room system according to an embodiment of the present invention. Note that the embodiment of the present invention is a form applied to a semiconductor wafer manufacturing site provided in a clean room,
Clean air from which pollutants are removed and which has low dew point is used as clean gas.

<First Embodiment> A schematic configuration of a clean room system according to the present embodiment will be described with reference to FIG. The clean room system according to the present embodiment is installed in an existing clean room 100. The existing clean room 100 is a circulation-type clean room. The space above the ceiling is an upper return plenum chamber 101, and the space below the floor is a lower return plenum chamber 102. The ceiling of the existing clean room 100 is a fan filter unit (FF
U) 103, and the floor surface is formed by a breathable grating floor 104. That is, the existing clean room 100, the lower return plenum chamber 103, and the upper return plenum chamber 101 constitute a circulation path of a clean atmosphere in the existing clean room.

The clean system according to the present embodiment is a housing disposed in an existing clean room 100 and has a handling chamber 4 having a clean space 1 inside, and a dust and gaseous contaminant under the floor of the existing clean room 100. A clean air supply device (clean gas supply means) 2 for supplying clean air having a low dew point to the handling chamber 4 from which contaminants including odors are removed, and a charged substance in the handling chamber 4 which is disposed on the top surface of the handling chamber 4. A soft X-ray irradiator 3 which is a neutralizing means for electrically neutralizing. The clean air supply device 2 and the handling chamber 4 are connected by a supply duct 5. The soft X-ray irradiator 3 irradiates the soft space 1 with soft X-rays having a wavelength range of 1 to 100 angstroms. A differential pressure exhaust port 6 serving as an exhaust unit is provided at a lower portion of the side surface of the handling chamber 4 at a position distant from the soft X-ray irradiation device 3. A differential pressure damper (not shown) that opens in the differential pressure exhaust port 6 only when the clean space 1 is maintained at a positive pressure with respect to the existing clean room 100.
Is provided.

In the existing clean room 100, a wafer manufacturing apparatus 7 is disposed adjacent to the handling chamber 4. A first opening / closing door 8 is provided on a side surface of the handling chamber 4 on the side of the wafer manufacturing apparatus 7, and a second opening / closing door 9 is provided on a side surface facing the first opening / closing door 8.
A wafer transfer box 10 for storing a predetermined number of wafers is detachably attached to the handling chamber 4 outside the second opening / closing door 9. In the handling chamber 4, a handling arm 11 for transferring (handling) a wafer between the first opening and closing door 8 and the second opening and closing door 9 is arranged. The existing clean room 10
0, a transport vehicle 12 that transports the wafer transport box 10
Is arranged. The soft X-ray irradiator 3 is configured to operate in conjunction with the first door 8,
When the first opening / closing door 8 or the second opening / closing door 9 is closed, the soft X-ray irradiation is automatically terminated after a lapse of a predetermined time when the soft X-ray is irradiated in the open state. The wafer transfer box 10 is a box that hermetically seals the inside of the box when gripped by the arm of the transfer vehicle 12.

As shown in the system diagram of FIG. 2, the clean air supply device 2 has a first rotor 13, a second rotor 14, and a third rotor 15 containing metal silicate or the like as an adsorbent. are doing. First rotor 13, second rotor 1
4. The third rotor 15 is arranged so as to traverse the purification air passage R1 through which the outside air from which dust has been removed passes and to cross the regeneration air passage R2 through which air heated to the regeneration temperature of the adsorbent passes. I have. At the same time, the second rotor 14 and the third rotor 15 are arranged so as to cross the purge air passage R3 through which the air exiting the purification air passage R1 passes. The regeneration temperature of the adsorbent is a temperature at which the gaseous pollutants and water collected by the metal silicate and the like are desorbed and released.

The purge air passage R3 branches from the outlet side of the purification air passage R1 of the third rotor 15, passes through the third rotor 15, and merges with the regeneration air passage R2. Similarly, the second rotor 14 branches off from the outlet side of the purification air passage R1 of the second rotor 14, passes through the second rotor 14, and merges with the regeneration air passage R2. Regeneration airway R2
Is branched from the outlet side of the purifying passage R1 of the third rotor 15.

In each of the ventilation paths of the clean air supply device 2, coolers C1 to C5 for cooling the air in the ventilation paths to a predetermined temperature.
C4 and a damper D1 for adjusting the air flow rate in the ventilation path
To D8, the fans F1 to F6, and the heaters H1 to H4 for heating the air in the ventilation path to a predetermined temperature are arranged at appropriate places. Note that the outside air passing through the purification air passage R1 has been adjusted in advance such as dust removal by an outside air conditioner (not shown).

The second rotor 14 and the third rotor 15 are shown in FIG.
As shown in FIG. 3, a rotatable cylindrical dehumidifying and purifying section 14a in which an adsorbent such as a metal silicate is stored, and a through hole fixed to both ends of the dehumidifying and purifying section and penetrating in the axial direction. Purification inlet 14c (15c), regeneration outlet 14d
(15d), a pair of end panels 14b, 14b having a purge outlet 14e (15e) at a predetermined position. The purification inlet 14c (15c) is connected to the purification air passage R1, and the regeneration outlet 14d (15d) is connected to the regeneration air passage R
2, and the purge outlet 14e (15e) is connected to the purge air passage R3. Although not shown, the first rotor 13 has the same configuration as the second rotor 14 and the third rotor 15 except that a purge outlet is not provided. Examples of the adsorbent include silica gel and alumina in addition to metal silicate.

Further, as shown in the system diagram of FIG. 4, the clean air supply device 2 may be configured to use both air dehumidifying means and gaseous pollutant removing means. This clean air supply device has adsorption towers 17 and 17 which are arranged so as to simultaneously include a part of the purification air passage R1 and a part of the regeneration air passage R2 and filled with zeolite. A chemical filter 16 that captures gaseous pollutants is disposed in the purification air passage R1 downstream of the adsorption tower 17. From the regeneration air passage R2, a part of air before passing through the adsorption tower 17 is sent to the purification air passage R1, and a part of air after passing through the adsorption tower 17 is sent to the purification air passage R1. There is a branch from the ventilation path you care about. Further, in this clean gas supply device, the purification air passage R1 and the regeneration air passage R2 are provided with the adsorption tower 1
Branches before and after 7 and 17 so that the outside air for purification or the air for regeneration can be independently supplied to each adsorption tower 17. The cooler, the heater, the damper, and the fan are appropriately arranged in each ventilation path, similarly to the clean air supply device 2 shown in FIG.

Next, the operation of the clean room system according to this embodiment will be described. First, supply of clean air by the clean air supply device 2 will be described. The outside air introduced into the purifying passage R1 is cooled and dehumidified by the cooler C1. At the same time, low temperatures are generally preferred conditions for the adsorption of gaseous pollutants and moisture,
The outside air is adjusted to a temperature suitable for the adsorption of gaseous pollutants and moisture by the adsorbent by the cooler C1, and then passes through the first rotor 13 rotating at a predetermined speed. In addition, the first rotor 13 moves in the direction passing through the purification inlet and the regeneration outlet,
The second rotor 14 and the third rotor 15 rotate in a direction passing through a purification inlet, a regeneration outlet, and a purge outlet, respectively. The outside air passing through the first rotor is similarly cooled by the cooler C2,
After being adjusted to an appropriate temperature by C3, it passes through the second rotor 14 and the third rotor 15. The outside air that has passed through the third rotor 15 is removed until gaseous pollutants become 1 ppb or less.
And it is clean and dry air (clean air) having a dew point of -100 ° C or less. The clean air passing through the third rotor 15 is supplied to the cooler C4 and the heater H1.
After the temperature is adjusted to an appropriate temperature, the air is continuously supplied to the clean space 1 through the supply duct 5.

Clean air that has passed through the third rotor 15 is supplied to the regeneration air passage R2 from the purification air passage R1. The clean air supplied to the regeneration air passage R2 is heated by the heater H2 to the regeneration temperature of the adsorbent, passes through the third rotor 15, and joins the purge air of the third rotor 15. The air in the regeneration air passage R2 that has merged with the purge air of the third rotor 15 passes through the second rotor 14 after being heated to the regeneration temperature again by the heater H3, and merges with the purge air of the second rotor 14. The air in the regeneration air passage R2 that has merged with the purge air of the second rotor 14 passes through the first rotor 13 after being heated to the regeneration temperature again by the heater H4. The air supplied to the regeneration ventilation passage R2 and passed through each rotor is exhausted to the outside.

Air that has passed through the second rotor 14 and the third rotor 15 is supplied to the purging passage R3 from the purifying passage R1. The purge air passage R3 branched from the outlet side of the purification air passage R1 of the third rotor 15 has a third passage.
The clean air that has passed through the rotor 15 is supplied, and after passing through the third rotor 15, the clean air merges with the regeneration air passage R2. Similarly, air that has passed through the second rotor 14 is supplied to the purge air passage R3 that branches off from the outlet side of the purification air passage R1 of the second rotor 14, and the air that has passed through the second rotor 14 is used for regeneration. Merges with the ventilation path R2.

Since the first rotor 13, the second rotor 14, and the third rotor 15 are rotating at a predetermined speed in the above-described direction, the first rotor 13, the second rotor 14, and the third rotor 15 collect gaseous pollutants and moisture in the outside air of the purifying passage R1. Each of the collected surfaces traverses the regeneration air passage R2, and the gaseous pollutants and moisture are desorbed and released from the collected surface, and the collected surface is regenerated. Further, the collecting surfaces of the second rotor 14 and the third rotor 15 are provided with the regeneration air passage R.
After crossing the purge air passage R3 after crossing 2, the regenerated trapping surface is cooled. That is, the dehumidifying and purifying units 14a, 1a of the second rotor 14 and the third rotor 15
5a is divided into a purification zone, a regeneration zone, and a purge zone (divisions indicated by broken lines in FIG. 3) from a very short-term viewpoint.

In the case where the clean air supply device shown in FIG. 4 is used, the outside air is passed through one adsorption tower 17 and the air for regeneration is passed through the other adsorption tower 17.
Opening and closing the nozzles 16 to 16, the clean air is continuously supplied as in the case of the clean air supply device 2 shown in FIGS. Although zeolite has an adsorbing action for gaseous pollutants in addition to the dehumidifying action, as in the above-described adsorbent, the adsorbing action has selectivity and cannot cope with some gaseous pollutants. In order to adsorb gaseous pollutants that cannot be adsorbed by zeolite, a chemical filter 16 is used.
Is used. As described above, the chemical filter 16 complements the adsorption of gaseous pollutants by zeolite, and a specific example of such a chemical filter 16 is an activated carbon filter.

The clean space 1 is kept in a clean state in which gaseous pollutants and moisture have been substantially removed by the clean air manufactured as described above. When the first opening / closing door 8 is opened in this clean state, the soft X-ray irradiating device 3 emits soft X-rays in conjunction with the opening of the first opening / closing door 8. The handling arm 11 receives a semiconductor wafer as a manufactured product from the wafer manufacturing apparatus 7.

The semiconductor wafer is charged when handled by the handling arm 11. On the other hand, the soft space 1 receives soft X-ray irradiation from the soft X-ray
The clean gas inside is ionized. Ion N ₂ ⁺ generated at this time, O ₂ ^+, O ₂ ^- and is, electrons e along with ionization ^- also occurs. Therefore, N ₂ generated by soft X-ray irradiation
⁺ Adheres to the surface of the semiconductor wafer and electrically neutralizes the semiconductor wafer. Further, since the energy of the soft X-rays is sufficient to ionize oxygen, the generation of oxygen radicals due to the ionization of oxygen is prevented, so that the generation of ozone in the clean space 1 is prevented.

When the semiconductor wafer is electrically neutralized on the handling arm 11, the second door 9 of the handling chamber 4 opens. Then, the semiconductor wafer is stored in the wafer transfer box 10 by the handling arm 11.

A predetermined number of sheets (for example, 2
When five (5) semiconductor wafers are taken out, the first opening / closing door 8 is closed, and when a predetermined number of semiconductor wafers are stored in the wafer transfer box 7, the second opening / closing door 9 is closed. In addition, when the above-described predetermined time elapses after the first opening / closing door 8 or the second opening / closing door 9 is closed, the irradiation from the soft X-ray irradiation device 3 automatically ends.

The wafer transfer box 10 containing a predetermined number of semiconductor wafers is transferred by the transfer vehicle 12 to the next step. Since the wafer transport box 10 is gripped and transported by the arm of the transport vehicle 12, the inside of the box is airtightly sealed.

Since the handling chamber 4 forming the clean space 1 is provided with the differential pressure exhaust port 6, when the clean space 1 is at a positive pressure with respect to the existing clean room 100, the clean air in the clean space 1 is removed. Is released outside the clean space 1. Therefore, by adjusting the amount of clean air supplied by the clean air supply device 2, the number of ventilations required for handling semiconductor wafers in the clean space 1 is ensured.

Table 1 shows actual measured values of the static elimination effect and the surface contamination prevention effect in the clean room system according to the present embodiment. Note that A to D in Table 1 are conditions for comparison and are as follows. Condition A: The semiconductor wafer was handled in general air (outside air) without performing static elimination. Condition B: Static electricity was removed in ordinary air to handle the semiconductor wafer. Condition C: The semiconductor wafer was handled in a low dew point air (dry air) prepared using a conventional dehumidifier without removing contaminants without removing electricity. Condition D: Static electricity was removed in the dry air where contaminants were not removed, and the semiconductor wafer was handled.

[0047]

[Table 1]

The above-mentioned handling is an operation in which a pre-treatment for cleaning the surface with dilute hydrofluoric acid and removing a natural oxide film is performed, and then the wafer is taken in and out of a 25-piece wafer transfer box. It took about 30 minutes to put and take out 25 semiconductor wafers.

From Table 1, the following facts can be understood regarding the effect of removing static electricity from semiconductor wafers and the effect of preventing contamination by gaseous contaminants. Regarding the static elimination effect, it can be seen that when static elimination was performed (conditions B and D), the static elimination was completely completed regardless of the atmosphere of the handling operation. On the other hand, the charge amount of the semiconductor wafer exceeds -1000 V under the condition (No condition A, Condition C) in which static elimination is not performed, and particularly under the condition C performed in dry air, the charge amount shows the largest charge amount of -2500 V. I have.

Next, regarding the amount of organic matter deposited, the handling operation in this system is less than the measurement limit value, whereas the measurement limit value is 50 to 1 in any of the conditions A to D.
It can be seen that 80 times as many organic substances are attached. Of these, under the dry air atmosphere conditions B and D, the amount of contamination is small, indicating that some organic substances have been removed during the dry air production. Also, it should be noted that when comparing in the same atmosphere, that is, when comparing the condition A and the condition B, or when comparing the condition C and the condition D, the organic matter adhesion amount is higher when the charge is removed. Is big. This proves that if the gaseous contaminants are not sufficiently removed at the time of static elimination, the contamination by the gaseous contaminants is promoted along with ion attachment.

As can be understood from the above description, the clean room system according to the present embodiment is a clean air supply device for removing contaminants including dust and gaseous contaminants and supplying clean air having a low dew point to the clean space 1. 2
And the soft X-ray irradiator 3 for irradiating the soft space 1 with the soft X-ray, it is possible to prevent the contamination of the semiconductor wafer surface due to the attachment of gaseous contaminants to the semiconductor wafer and the attachment of moisture. At the same time, since electrostatic damage can be prevented, the reliability and yield of the manufactured semiconductor wafer can be improved.

Further, the clean air supply device 2 of the clean room system according to the present embodiment has a configuration in which an adsorbent such as a metal silicate is accommodated, and purification and dehumidification are performed by passing outside air through a three-piece rotor rotating at a predetermined speed. Therefore, it is possible to continuously and inexpensively produce clean air having a contaminant concentration of 1 ppb or less and a dew point of -100 ° C. or less.

Further, since the soft X-ray irradiator 3 of the clean room system according to the present embodiment is configured to irradiate the soft X-ray to the clean space 1, the clean air in the clean space 1 is quickly ionized. Since the charge of the semiconductor wafer is electrically neutralized by the ions or electrons of the clean air, even if the ions or electrons of the clean gas adhere to the semiconductor wafer, they do not become contaminants or hardly become contaminants. And, since the energy to be irradiated is large, it is possible to quickly remove electricity from the semiconductor wafer and to ionize oxygen without generating oxygen radicals, thereby preventing generation of ozone having strong oxidizing power. .

Since the soft X-ray irradiator 3 is configured to turn on / off the irradiation of soft X-rays in conjunction with the first opening / closing door 8 or the second opening / closing door 9 of the handling chamber 4,
After the lapse of the predetermined time, the irradiation of the soft X-ray is automatically terminated, so that the power of the soft X-ray irradiation device 3 can be saved.

In the clean room system according to the present embodiment, the clean space 1 is provided in the existing clean room 100.
Is provided in the handling chamber 4 so that air can be prevented from flowing into the clean space 1 from the existing clean room 100 and the clean space 1 can be prevented. At the time of positive pressure, the clean air in the clean space 1 is exhausted to the outside of the clean space 1 in conjunction with the supply of the clean air supply device 2, so that the ventilation frequency suitable for the clean space 1 can be secured.

<Second Embodiment> The clean room system according to the present embodiment returns clean air from the clean space 1 to the clean air supply device 2 instead of exhausting clean air from the differential pressure exhaust port. This embodiment is different from the first embodiment in that clean air is regenerated and the number of times of ventilation of the clean space 1 is ensured. In the description of the present embodiment, the same components as those of the above-described first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

More specifically, the clean room system according to the present embodiment returns the clean air in the clean space 1 to the clean air supply device 2 instead of the differential pressure exhaust port 6 as shown in FIG. A duct 18 is provided. The return duct 18 is connected to the purge air passage R3 of the clean air supply device 2 (the regeneration air passage R2 in the case of the clean air supply device shown in FIG. 4).

The clean room system according to the present embodiment differs from the first embodiment in the configuration of the differential pressure exhaust port 6 and the return duct 18, but according to the configuration, the damper of the clean air supply device 2 is used. By adjusting the opening and the amount of air blown by the fan so that the supply amount of clean air to the clean space 1 is an appropriate supply amount, the number of ventilations required for the work of transporting semiconductor wafers to the clean space 1 is ensured. Can be.

Further, in the clean room system according to the present embodiment, in addition to the effects of the first embodiment, the clean air in the clean space 1 is returned to the purge air passage R3 by the clean air supply device 2. Therefore, the amount of clean air supplied from the purifying air passage R1 to the purging air passage R3 is reduced, and the reduced amount of clean air is supplied to the clean space 1. Can be manufactured.

<Third Embodiment> A clean room system according to the present embodiment is an existing clean room 1
The second embodiment is different from the first embodiment in that a semiconductor wafer handling operation is performed between a plurality of wafer manufacturing apparatuses 7 installed in the semiconductor wafer 00. In the description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

More specifically, as shown in FIG. 6, the clean room system according to the present embodiment uses a handling tunnel 24 instead of the handling chamber 4.
Is provided. The handling tunnel 24 is shown in FIG.
, And a plurality of wafer manufacturing apparatuses 7 are arranged along the handling tunnel 24. In the handling tunnel 24, a wafer transfer device 22 that moves along the longitudinal direction of the handling tunnel 24 (perpendicular to the plane of FIG. 6) is disposed. The wafer transfer device 22 has the handling arm 11 on the upper part. Other configurations are the same as those of the above-described first embodiment except that the second opening / closing door 9 is not provided.

According to the above configuration, the wafer transfer device 22 takes out the semiconductor wafer from the first opening / closing door 8, moves in the handling tunnel 24 along the longitudinal direction of the handling tunnel 24, and transfers the semiconductor wafer to another wafer manufacturing device. .

In the clean room system according to the present embodiment, the semiconductor wafer can be handled between the plurality of wafer manufacturing apparatuses 7 by the above configuration. Although there is a difference from the first embodiment in the arrangement of the handling chamber 4, the handling tunnel 24, and the wafer manufacturing apparatus 22 provided with the handling arm 11, the semiconductor in the clean space 1 formed by the handling tunnel 24 is different. It is possible to prevent the contamination of the semiconductor wafer surface due to the attachment of gaseous contaminants and moisture to the wafer, and also to prevent electrostatic interference, thereby improving the reliability and yield of the manufactured semiconductor wafer. In common. Other effects are the same as those of the first effect described above, and a description thereof will be omitted.

<Fourth Embodiment> The clean room system according to the present embodiment is different from the third embodiment in that clean air partially ionized is supplied to the clean space 1. In the description of this embodiment, the same components as those of the above-described third embodiment are denoted by the same reference numerals, and description thereof will be omitted.

The clean room system according to the present embodiment includes a soft X-ray irradiator 3 disposed in a supply duct 5 as shown in FIG. Further, the differential pressure exhaust port 6 is provided at a position away from the opening of the supply duct 5 on the clean space 1 side, that is, at the upper side of the handling tunnel 24.

In the clean room system according to the present embodiment, in addition to the effects of the third embodiment described above, since a part of the clean air supplied to the clean space 1 is ionized in the supply duct 5, The generated ions are widely dispersed in the clean space 1, and the wider charged surface can be efficiently neutralized electrically.

<Fifth Embodiment> A clean room system according to a fifth embodiment of the present invention
The present embodiment is different from the first embodiment in that the present invention is applied to a temporary storage of semiconductor wafers instead of. In the description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the clean room system according to the present embodiment
, A temporary storage 2 that forms a clean space 1 inside
5 is disposed in the existing clean room 100. The transfer of the semiconductor wafer between the wafer manufacturing apparatus 7 and the temporary storage 25 is performed by the wafer transfer box 1 in which the semiconductor wafer is stored.
This is carried out by a transport vehicle 12 that transports 0s.

The temporary storage 25 temporarily stores the semiconductor wafers in a state of being stored in the wafer transfer box 10 and is connected to the supply duct 5 at the upper side. The temporary storage 25 includes a ULPA filter 26 that is a clean gas filtering unit that removes dust from the supplied clean air, a soft X-ray irradiator 3 that ionizes clean air that has passed through the ULPA filter 26, and a wafer transfer box 10. A second opening / closing door 9 serving as a loading / unloading port and a differential pressure exhaust port 6 are provided. The ULPA filter 26 may be disposed in at least one of the clean air supply device 2, the supply duct 5, and the temporary storage 25.

According to the above configuration, the wafer transfer box 1
It is possible to eliminate static electricity generated when a semiconductor wafer is put in and taken out of the storage box 25 and the wafer transfer box 10 is put in and out of the temporary storage 25. Further, since the time during which the semiconductor wafer is stored in the temporary storage 25 is longer than the handling in the above-described embodiment, the semiconductor wafer is easily affected by the storage state. Therefore, by setting the atmosphere of the temporary storage 25 to be clean air and performing static elimination, it is possible to maintain a good storage state of the semiconductor wafer. Note that other effects are the same as those of the first embodiment described above, and a description thereof will be omitted.

<Sixth Embodiment> The clean room system according to the present embodiment returns clean air from the clean space 1 to the clean air supply device 2 instead of exhausting clean air from the differential pressure exhaust port 6. The fifth embodiment is different from the fifth embodiment in that clean air is regenerated and the number of ventilations of the clean space 1 is ensured. In the description of this embodiment, the same components as those of the above-described fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.

In the clean room system according to the present embodiment, more specifically, as shown in FIG. 9, a return duct for returning the clean air in the clean space 1 to the clean air supply device instead of the differential pressure exhaust port 6. 18 is provided in the temporary storage 25. The return duct 18 is connected to the purge air passage R3 of the clean air supply device 2 (the regeneration air passage R2 in the case of the clean air supply device shown in FIG. 4).

Although the clean room system according to the present embodiment has the above-described difference in configuration, by temporarily adjusting the supply amount of clean air from the clean air supply device 2, the temporary storage of semiconductor wafers in the clean space 1 is performed. The required ventilation frequency can be secured. Further, for the same reason as in the above-described second embodiment, clean air can be manufactured at lower cost.

<Seventh Embodiment> The clean room system of the present embodiment is different from the first embodiment in that the clean air in the clean space 1 is circulated. In the description of the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

More specifically, in the clean room system according to the present embodiment, as shown in FIG. 10, a clean space 1 is provided above a handling chamber 4 so as to cancel heat generated by work in the clean space 1. A cooling coil 27 which is a temperature control means for controlling the temperature of the air, a ULPA filter 26 for collecting dust generated in the clean space 1, and a clean air temperature controlled by the cooling coil 27 pass through the ULPA filter 26. A fan F7 for blowing air is provided. In the present embodiment, the cooling coil 27 is shown as the temperature control means, but a heating device such as a heater may be used or used in combination.

According to the above configuration, in addition to the effects of the first embodiment, even if heat or the like is generated in the clean space 1 due to the operation of the handling arm 11, the clean coil 1 can appropriately clean the clean space 1. Controlled by temperature. Therefore, it is possible to prevent the semiconductor wafer from being denatured due to a temperature change in the clean space 1 due to the heat generation or the like.

In the clean room system according to the present embodiment, a clean air circulation path in the clean space 1 is formed, and the ULPA filter 26 is disposed in the circulation path. Even if dust is generated in the clean space 1, it is collected by the ULPA filter 26, so that particle contamination of the semiconductor wafer due to dust generation in the clean space 1 can be prevented. For these reasons, the clean room system according to the present embodiment can further improve the reliability and yield of semiconductor wafers.

<Eighth Embodiment> A clean room system according to the present embodiment differs from the first embodiment in that handling is performed between semiconductor wafer production apparatuses that perform different operations. In the description of the present embodiment, the same components as those of the above-described first embodiment will be denoted by the same reference numerals, and detailed description thereof will be omitted.

More specifically, in the clean room system according to the present embodiment, open / close valves 28 and 29 are provided near the outlet of the supply duct 5 and the clean space 1 side of the differential pressure exhaust port 6 as shown in FIG. A vacuum pump 30 is provided to bring the clean space 1 into a reduced pressure state. Opening / closing valves 28 and 29 and vacuum pump 30
Is controlled based on the detection result of a pressure sensor (not shown) and in conjunction with the clean air supply device 2. With the above configuration, the clean space 1 maintains a predetermined reduced pressure state. That is, if the supply amount of clean air is increased, the pressure reduction of the clean space 1 is eased. Therefore, the amount of clean air intake by the vacuum pump 30 is adjusted according to the supply amount of clean air, and the reduced pressure state of the clean space 1 is set to a predetermined value. Is kept in a state.

In the case where a plurality of production apparatuses performing different operations are adjacent to the handling chamber 4, the cleanliness required in each production apparatus is different, or another production apparatus depends on the operation (process) performed in one production apparatus. May be contaminated. In such a case,
It is necessary to take measures to prevent the cross-contamination between the production devices by reducing the pressure in the space connecting the production devices such as the handling chamber 4 and the like.

The clean room system according to the present embodiment has a configuration in which the clean space 1 is maintained at a predetermined reduced pressure state in addition to the effects of the first embodiment described above. The space connecting the production apparatuses performing different operations is in a decompressed state, so that it is possible to prevent the spread or transmission of contamination between the production apparatuses (wafer manufacturing apparatus 7 in the present embodiment).

In the clean room system according to the present embodiment, since the clean space 1 is configured to be maintained at a predetermined reduced pressure, the charged potential of the semiconductor wafer before static elimination becomes −200 to −500 V, and the clean space 1 Pollutant concentration is lower than at normal pressure. Accordingly, it is possible to further reduce troubles due to the adhesion of gaseous contaminants and moisture to the semiconductor wafer in the clean space 1 and static electricity troubles.

[0083]

The clean room system according to the present invention comprises a clean gas supply means for removing contaminants including dust and gaseous contaminants and supplying a clean gas having a low dew point to a clean space, and a charged material in the clean space. For example, when the present invention is applied to a manufacturing site of an electronic device product, gaseous contaminants adhere to the electronic device product in a clean space, and adhesion of moisture and static electricity can be provided. Failures are prevented at the same time, and the reliability and manufacturing yield of the electrical device product can be improved.

Further, the clean room system of the present invention
More specifically, if the concentration of the contaminants in the clean gas is reduced to 1 ppb or less, and the moisture in the clean gas is removed so that the dew point of the clean gas is -20 ° C. or less, the electron The reliability and yield of the device product can be improved.

The clean room system of the present invention
If the static elimination means is a soft X-ray irradiator that irradiates clean gas with soft X-rays of 1 to 100 angstroms in a wavelength region, the energy of electromagnetic waves (X-rays) irradiated to the clean gas is sufficiently large. Even if oxygen is contained therein, ozone is not generated, so that corrosion and the like of the electronic device product can be prevented, and the charge in the clean space can be electrically neutralized within a short irradiation time.

The clean room system of the present invention
The provision of the temperature control means for controlling the clean space to a predetermined temperature can prevent the electronic device product or the like from being denatured due to the influence of heat generation or the like associated with the work content in the clean space. Reliability and yield can be further improved.

Further, the clean room system of the present invention
When the electronic device is provided with clean gas filtering means for collecting dust generated in the clean space, it is possible to collect dust generated in accordance with the work performed in the clean space, and the dust is generated in the clean space. Since the particle contamination of the product can be further reduced, the reliability and yield of the electronic device product can be further improved.

Further, the clean room system of the present invention
If a clean gas exhaust means for exhausting the clean gas from the inside of the clean space to the outside is provided, the clean space can be quickly returned to the clean state even when a large amount of pollutants are generated in the clean space. By linking the clean gas exhaust means with the clean gas supply means, it is possible to secure the number of ventilations according to the work content in the clean space and to adjust the conditions (cleanness, pressure, etc.) in the clean space. It is possible to set conditions suitable for the contents of work in the building.

The clean room system of the present invention
By providing a return duct for returning part of the clean gas in the clean space to the clean gas supply means, it is possible to reduce the clean processing amount of the gas in the clean gas supply means and to produce clean gas at lower cost. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing one embodiment of a clean room system of the present invention.

FIG. 2 is a system diagram of a clean air supply device shown as one embodiment of a clean gas supply means of the clean room system of the present invention.

FIG. 3 is a perspective view showing a rotor used in the clean air supply device shown in FIG. 2;

FIG. 4 is a system diagram of a clean air supply device shown as another embodiment of the clean gas supply means in the clean room system of the present invention.

FIG. 5 shows a second example of the clean room system of the present invention.
It is a schematic diagram showing an embodiment.

FIG. 6 shows a third embodiment of the clean room system according to the present invention.
It is a schematic diagram showing an embodiment.

FIG. 7 shows a fourth embodiment of the clean room system according to the present invention.
It is a schematic diagram showing an embodiment.

FIG. 8 shows a fifth embodiment of the clean room system according to the present invention.
It is a schematic diagram showing an embodiment.

FIG. 9 shows a sixth embodiment of the clean room system according to the present invention.
It is a schematic diagram showing an embodiment.

FIG. 10 is a schematic view showing a clean room system according to a seventh embodiment of the present invention.

FIG. 11 is a schematic view showing an eighth embodiment of the clean room system according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 Clean space 2 Clean air supply device (clean gas supply means) 3 Soft X-ray irradiation device 4 Handling chamber 5 Supply duct 6 Differential pressure exhaust port 7 Wafer manufacturing device 8 First open / close door 9 Second open / close door 10 Wafer transfer box 11 Handling arm 12 Conveyor vehicle 13 First rotor 14 Second rotor 14a, 15a Dehumidification purification processing unit 14b, 15b End panel 14c, 15c Purification inlet 14d, 15d Regeneration outlet 14e, 15e Purge outlet 15 Third rotor 16 Chemical filter 17 Adsorption tower 18 Return duct 22 Wafer transfer device 24 Handling tunnel 25 Temporary storage 26 ULPA filter 27 Cooling coil 28, 29 Open / close valve 30 Vacuum pump 100 Existing clean room 101 Upper return plenum chamber 102 Lower litter Plenum chamber 103 fan filter unit (FFU) 104 Gray quenching bed C1~C4 cooler D1~D17 damper F1~F7 fan H1~H4 heaters R1 purifying air passage R2 reproduction vapor passage R3 purge vapor passage

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Claims (8)

[Claims] 1. A clean gas supply means for removing a pollutant including dust and gaseous pollutants and supplying a clean gas having a low dew point to a clean space, and electrically neutralizes a charged material in the clean space. A clean room system comprising: a charge removing unit. 2. The method according to claim 1, wherein the concentration of the contaminant in the clean gas is 1 ppb or less.
The described clean room system. 3. The clean room system according to claim 1, wherein the clean gas has a dew point of −20 ° C. or less. 4. The clean room system according to claim 1, wherein said static eliminator is a soft X-ray irradiator for irradiating said clean gas with soft X-rays having a wavelength range of 1 to 100 Å. 5. The clean room system according to claim 1, further comprising temperature control means for controlling said clean space to a predetermined temperature. 6. The clean room system according to claim 1, further comprising a clean gas filtering unit that collects dust generated in the clean space. 7. The clean room according to claim 1, further comprising a clean gas exhaust unit that exhausts the clean gas from the inside of the clean space to the outside, wherein the clean gas exhaust unit is interlocked with the clean gas supply unit. system. 8. The clean room system according to claim 1, further comprising a return duct for returning a part of the clean gas in the clean space to the clean gas supply unit.