JPH06252242A - Transfer apparatus including gas purifying means - Google Patents

Abstract

PURPOSE:To provide a transfer apparatus wherein varieties of contaminating matters are removed and a purified space is ensured, and it has a closeable space. CONSTITUTION:In a transfer apparatus 1 having a closeable space, there is provided in the space gas purifying means including a photoelectron emitting material 7, an ultraviolet source 6 and/or a radiation means, and an electrode 8. Photoelectrons 10 produced by irradiation from the ultraviolet source 6, etc., turn fine particles 5 in the space to charged fine particles 11 which are collected by the electrode 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device having a gas cleaning means, and more particularly to a transfer device having a sealable space for transferring raw materials such as wafer liquid crystal, semi-finished products and products. The carrier device of the present invention is used in the semiconductor industry,
It can be used as a carrier for raw materials, semi-finished products, and products in various industries such as liquid crystal industry, agriculture and forestry industry, food industry, and precision machinery industry.

[0002]

2. Description of the Related Art A conventional technique will be described by taking a wafer transfer device in the semiconductor industry as an example. In order to prevent the contamination of the wafer with fine particles or the like, the wafer is transported (transport from the process A to the process B). As a transport method, 1) the transport space is evacuated or 2) high-purity nitrogen (N It has been proposed that ₂ ) be poured into the transport space. These methods have drawbacks such as 1) the cost for maintaining a vacuum in the vacuum method, the equipment and cost for emergency measures, and the problem of generation of fine particles due to pressure change (due to pressure change).
And 2) in a manner flowing N _2, it was such a problem of the impact on the surrounding environment due to the high purity N ₂ feed cost, the N ₂ to runaway.

Further, the conventional transfer device is merely for transferring the wafer, and when the operation is temporarily suspended for convenience, the wafer is taken out from the transfer device, stored in a stocker of another device, and contaminated. I was trying to prevent it. For example, in a weekend operation, a wafer is taken out of a transfer device, stored in a stocker of another device to prevent contamination, transferred to the transfer device at the beginning of the week, and sent to the next process. In such a transfer device, the operation is complicated and the chances of contamination of the wafer are increased, resulting in low yield and high cost.
Further, the above-mentioned device mainly deals with contamination of fine particles. The cause of wafer contamination is not only contamination by fine particles but also contamination by harmful gas that causes an increase in contact angle, for example, contamination by hydrocarbons (HC) in indoor air. Not not.

Here, the contact angle means the contact angle of wetting with water, and indicates the degree of contamination of the substrate surface. That is, when a hydrophobic (oil-based) substance adheres to the surface of the substrate, the surface repels water and becomes difficult to wet.
Then, the contact angle between the substrate surface and the water droplet becomes large. Therefore, if the contact angle is large, the degree of contamination is high, and conversely, if the contact angle is small, the degree of contamination is low.

[0005]

As described above, ultra-low concentration hydrocarbons (H) other than methane in the air caused by fine particles (particulate matter) and automobile exhaust gas are generated on the wafer.
Gaseous substances such as C) pose a problem as pollutants. In particular, HC is a gaseous harmful component, and extremely low concentrations of it in ordinary air (indoor air and outside air) cause pollution, so it is necessary to remove it. Further, various solvents (alcohols, ketones, etc.) generated during work in a clean room also pose a problem as pollutants.

That is, if the above-mentioned pollutants (fine particles and gaseous pollutants) are deposited on the substrate surface of wafers, semi-finished products, and products, the substrate surface is easily damaged and the productivity (yield) of semiconductor products is reduced. It is necessary to remove the pollutant because it causes the problem. Further, the transfer device has a drive part for transferring a wafer, and when an object moves, particles are inevitably generated. Therefore, an object of the present invention is to provide a transfer device having a sealable space in which various contaminants can be removed to obtain a clean space.

[0007]

In order to solve the above problems, according to the present invention, in a conveying device having a sealable space, a photoelectron emitting material, an ultraviolet ray source and / or a radiation source and an electrode are provided in the space. It is provided with the gas cleaning means. In the transfer device, a part of the sealable space may be a stocker, and the gas in the sealable space is one or more means selected from adsorption, absorption, ultraviolet ray and / or radiation irradiation. Is a gas purified to a concentration of non-methane hydrocarbons in the gas of 0.2 ppm or less, and the gas may be nitrogen.

The carrying means of the present invention can be applied to any carrying device such as a robot, a porcelain levitation, a belt conveyor, a bucket conveyor, etc., as long as it can be sealed. That is, at least the transport device,
By providing an ultraviolet ray source and / or a radiation source, a photoelectron emitting material, and an electrode, fine particles in the space of the transfer device (fine particles entrained in the wafer or fine particles generated by the transfer drive unit)
Are charged by the photoelectrons from the photoelectron emitting material, the charged fine particles are removed by the electrodes, the space of the transfer device is kept highly clean, and the contamination of the wafer can be prevented.

Depending on the type of the apparatus, a stocker having at least an ultraviolet ray source and / or a radiation source, a photoelectron emitting material, and an electrode may be integrated in the carrying space, so that the wafer being carried by the carrying apparatus may be changed depending on operating conditions. It can be stored in the stocker without taking it out. The stocker also charges the fine particles in the stocker by photoelectrons from the photoelectron emitting material, the charged fine particles are removed by the electrode, and the inside of the stocker is maintained highly clean. Further, it is possible to remove non-methane hydrocarbons in the gas to 0.2 ppm or less by using one or more kinds of means for adsorbing gas into the transfer space, absorbing means, ultraviolet ray and / or radiation irradiation means. Preferably, the contact angle of the wafer can be prevented from increasing.

Next, the individual components used in the present invention will be described in detail together with their operation. The photoelectron emitting material may be any as long as it emits photoelectrons upon irradiation with ultraviolet rays,
The smaller the photoelectric work function is, the more preferable. From the viewpoint of effect and economy, Ba, Sr, Ca, Y, Gd, La, C
e, Nd, Th, Pr, Be, Zr, Fe, Ni, Z
n, Cu, Ag, Pt, Cd, Pb, Al, C, Mg,
Au, In, Bi, Nb, Si, Ti, Ta, U, B,
Any one of Eu, Sn, P, W or a compound, alloy or mixture thereof is preferable, and these are used alone or in combination of two or more kinds. As the composite material, a physical composite material such as amalgam can also be used.

For example, the compounds include oxides, borides, and carbides, and the oxides include BaO, SrO, and Ca.
O, Y ₂ O ₅ , Gd ₂ O ₃ , Nd ₂ O ₃ , ThO ₂ , Z
rO ₂ , Fe ₂ O ₃ , ZnO, CuO, Ag ₂ O, La
₂ O ₃ , PtO, PbO, Al ₂ O ₃ , MgO, In ₂
O _3, BiO, NbO, there is such as BeO, also in borides _{is, YB 6, GdB 6, LaB} 5, NdB 6, Ce
_{B 6, BuB 6, PrB 6} , ZrB 2 include, as a further carbide UC, ZrC, TaC, TiC, Nb
C, WC, etc.

As the alloy, brass, bronze, phosphor bronze, an alloy of Ag and Mg (Mg is 2 to 20 wt%), C
An alloy of u and Be (1 to 10 wt% of Be) and an alloy of Ba and Al can be used, and the alloy of Ag and Mg, the alloy of Cu and Be, and the alloy of Ba and Al are preferable. . Oxide heats only the metal surface in air,
Alternatively, it can be obtained by oxidizing with a chemical. As another method, it is also possible to heat before use to form an oxide layer on the surface to obtain a stable oxide layer for a long period of time. As an example of this, an alloy of Mg and Ag can be formed into an oxide film on its surface under the temperature condition of 300 to 400 ° C. in water vapor, and this oxide film is stable for a long period of time.

Further, as the present inventor has already proposed, a photoelectron emitting material having a multiple structure can also be preferably used (Japanese Patent Laid-Open No. 1-155857). Further, a substance capable of emitting photoelectrons in a thin film form may be added to an appropriate base material and used (Japanese Patent Application No. 2-278123). As an example of this, there is a thin film of Au added as a substance capable of emitting photoelectrons on quartz glass as a UV transparent substance (base material) (Japanese Patent Application No. 2-295423). The shapes of these materials used are rod, cotton, lattice, plate,
It may be any shape such as pleated shape, curved surface shape, wire mesh shape,
A shape having a large irradiation area of ultraviolet rays and a large contact area with the treatment air is preferable.

The emission of photoelectrons from the photoelectron emitting material can be effectively carried out by appropriately using an opposite surface, a curved reflecting surface, etc., as previously proposed by the present inventor (JP-A-63). -100955). The shape and structure of the photoelectron emitting material and the reflecting surface differ depending on the shape and structure of the device or desired effect, and can be appropriately determined. The irradiation source for emitting photoelectrons from the photoelectron emitting material may be any one as long as it emits photoelectrons by irradiation. In addition to ultraviolet rays, electromagnetic fields, lasers, and radiation are applicable fields,
The device scale, shape, effect, etc. can be selected and used. Among these, ultraviolet rays or radiation is usually preferable in terms of effects and operation surface.

Any kind of ultraviolet light may be used as long as the photoelectron emitting material can emit photoelectrons by its irradiation.
Depending on the field of application, those having a sterilizing action are also preferable. The type of UV light depends on the application field, work content,
It can be appropriately determined depending on the use, economy and the like. As the ultraviolet ray source, any ultraviolet ray source can be used, and it can be appropriately selected and used depending on the application field, the shape of the device, the structure, the effect, the economical efficiency and the like. For example, a mercury lamp, a hydrogen discharge tube, a xenon discharge tube, a Lyman discharge tube, or the like can be used as appropriate.

It is also important to eliminate static electricity in the closed space of the transfer device. For example, when dust removal by photoelectrons and static elimination or potential reduction by irradiation of the ultraviolet rays are desired at the same time, the static elimination becomes remarkable when short wavelength ultraviolet rays are used. An example of this is a deuterium lamp. As described above, the present invention is characterized in that it has not only the dust removal function but also a contact angle increase prevention function and a charge removal function. By irradiating with radiation instead of irradiating with ultraviolet rays, the fine particles are similarly charged and the same effect can be obtained. The present inventor has already proposed irradiation of radiation (Japanese Patent Application Laid-Open No. 62-24459).

Soft X-rays as a radiation source
Is preferable in some fields of use because it has a remarkable effect of removing static electricity from the dust removing effect of photoelectron emission. In addition, a photoelectron emission device in which an ultraviolet source and a photoelectron emission material have been already proposed by the present inventor, for example, a device in which a thin film photoelectron emission material is coated on the surface of an ultraviolet lamp (Japanese Patent Application No. 3-22685).
No.); or a device for charging / collecting fine particles in which an ultraviolet source is surrounded by a photoelectron emitting material and an electrode and integrated into a unit (Japanese Patent Application No. 3-261289).

Any material can be used for the electrode material as long as it is a conductor, and various electrode materials for known charging devices can be preferably used. Usually, the electrode material is used for both the electric field setting described later and the charged fine particle collecting material described later. As the collecting material (dust collecting material) for the charged fine particles, any material can be used as long as it can collect the charged fine particles. Various electrode materials such as a dust collecting plate and a dust collecting electrode in a normal charging device can be used.

The electrode and / or the photoelectron emitting material is installed in a part of the space at an appropriate position in the space where the particles are present so that an electric field can be formed between the electrode and the photoelectron emitting material. ) And an electrode (+), an electric field (electric field) is formed. The electric field efficiently emits photoelectrons from the photoelectron emitting material, the photoelectrons charge fine particles in the space of the carrier, and the charged fine particles are collected by the electrodes, so that the space of the carrier becomes highly clean.

The position and shape of the electrode or the photoelectron emitting material can be appropriately selected depending on the space in which the particles are present, and the applied voltage for the electric field can be lowered, and the photoelectrons from the photoelectron emitting material charge the particles in the space. Any method may be used, and it can be appropriately determined by a preliminary test or the like in consideration of the field of use, device scale, shape, effect, economy, and the like. The closer the installation distance between the electrode and the photoelectron emitting material is, the lower the applied voltage may be, which is preferable. Generally, it is within 30 cm, preferably within 10 cm, but can be appropriately determined depending on the scale of the device, the field of use, and the like.

In the present invention, since the gas does not flow, the electric field voltage used in the present invention is effective even in a weak electric field, and the electric field voltage is 0.1 V / cm to 2 kV / cm. The suitable electric field strength depends on the field of application, conditions, device shape,
It can be decided by conducting preliminary tests and examinations appropriately in terms of scale, effect, economic efficiency, etc. The gas to the transfer device may be a gaseous harmful component (mainly C.H.), which will be described later, depending on the type of the transferred product (for example, the type of wafer or liquid crystal glass) or the surface condition of the substrate (surface treatment by the process). Should be removed.

The removal of non-methane hydrocarbons, or gaseous harmful components, adsorbs and / or adsorbs those components which increase the contact angle.
Alternatively, a method of collecting / removing with a material that absorbs, or a method of irradiating a gas with ultraviolet rays and / or radiation to collect / remove the generated secondary product, or generating ozone by irradiation to generate a complex oxidation It can be performed by a method of contacting with a physical catalyst. Non-methane hydrocarbons cause pollution at concentrations in various gases used in a clean room such as ordinary air (indoor air and outdoor air), nitrogen, and argon.

Among various non-methane hydrocarbons, the component that increases the contact angle is considered to differ depending on the type of base material (wafer, glass material, etc.) and the type and properties of the thin film on the substrate. As a result of intensive studies, the present inventor has found that it is effective to remove non-methane hydrocarbons as an index to 0.2 ppm or less, preferably 0.1 ppm or less. The removal of non-methane hydrocarbons by the adsorption and / or absorption means is the following method, which the present inventor has previously filed.

As the adsorbent, activated carbon, silica gel, synthetic zeolite, molecular sieve, high molecular compound (for example, styrene polymer, styrene-divinylbenzene copolymer), glass, fluorine compound, metal or metal oxide (eg, , TiO ₂ ) or the like is used. As a glass material,
Oxide glass systems such as silicate glass and phosphate glass are common. In particular borosilicate glass as a silicate glass (major _{component: N 2 O-B 2 O} 3 -SiO 2)
However, it is preferable because it is easy to mold, has a high adsorption effect, and is inexpensive. In addition, Ti, Au, Al,
When a metal thin film such as Cr is coated and used, the adsorption effect is enhanced.

As the fluorine compound, tetrafluoride resin, tetra-hexafluoride resin, PFA resin, trifluoroethylene resin,
Examples include tetrafluoroethylene-ethylene copolymer, vinylidene fluoride resin, vinyl fluoride resin, fluorinated graphite, and Teflon. The shapes of the glass and the fluorine compound used include a filter shape, a fiber shape, a net shape, a spherical shape, a pellet shape, a lattice shape, a rod shape, and a pleat shape. In general, a filter shape is preferable because it has a large adsorption effect. As an example of a molding method in the case of using in a filter shape, there is a method of using a fluorine compound resin as a binder and solidifying a fibrous glass material in a filter shape. When used in such a filter shape, dust removal performance is added to the HC removal performance, so a filter configuration is preferable.

Further, the adsorbent has an H.V.
C. Since there are multiple types of adsorbents, two adsorbents with different characteristics
It is preferable to use a combination of more than one kind. For example, when silica gel and a fibrous glass material containing a fluorine compound resin as a binder are used in combination, when fine particles (particulate matter) are generated from the upstream adsorbent (silica gel) or its surroundings (because fine particles become a pollution source. However, since a fibrous glass material having a fluorine compound resin as a binder is used in the form of a filter in the downstream, dust removal is preferable. Therefore, it is preferable to incorporate such an adsorbent into the device depending on the field of use, the scale of the device, and the shape of the device.

Examples of metals include Fe, Ag, Ni,
There are Cr, Ti, Au, and Pt, and powder, plate, sponge, cotton, fiber, or those added to an appropriate carrier, for example, silica-alumina gel supporting Ag or zirconium phosphate. A shape supporting Ag can be preferably used. Of the above adsorbents, silica gel, synthetic zeolite, polymer compounds, glass, fluorine compounds, and metals are more preferable because of their high adsorption effect. These adsorbents can be used alone or in appropriate combination of two or more kinds (Japanese Patent Application Nos. 3-341802 and 4-18053).
(See No. 8).

As will be described later, H which is involved in increasing the contact angle
Since C is considered to be a plurality of types, if two or more types of adsorbents are used in combination, the life becomes long. That is, since there is a limit to the collection of all the HCs involved in the increase of the contact angle depending on the collection by one kind of adsorbent, adsorbents having different adsorption characteristics should be used by conducting an experiment and appropriately combining them. It is effective. Further, since the degree of influence of HC varies depending on the type of conveyed product (for example, the type of wafer or liquid crystal glass) or the surface condition of the substrate (surface treatment by process), the field of use, device scale, shape, device A suitable test can be selected from the above-mentioned adsorbents by carrying out a preliminary test as appropriate according to use conditions, shared gas, required performance, economical efficiency and the like.

Depending on the field of application and type of device,
If the air to be treated is dehydrated, dehumidified, or dehumidified before air is passed through the adsorbent, the adsorbability of the adsorbent is improved and the service life is extended. For that purpose, cooling type, adsorption type, absorption type, compression type,
A well-known method such as a method by membrane separation can be used, and a preliminary test is appropriately performed depending on the application field, scale, shape, use conditions (for example, under atmospheric pressure or under pressure) of the device of the present invention, and one type Alternatively, two or more kinds are appropriately combined and used. As the dehumidification method, it is preferable to use a dehumidification method that maintains stable dehumidification performance over a long period of time, usually from several months to half a year or more.

Particularly, the cooling type and / or the adsorption type is simple and effective. The cooling type is preferably an electronic dehumidification system or a cooling coil system, and the adsorption type is simple to dehumidify and regenerate the dehumidifier itself while continuously dehumidifying (fixed type, rotary type, etc.). Is effective. As the adsorption-type dehumidifying material, silica gel, zeolite, activated carbon, activated alumina, magnesium perchlorate, calcium chloride or the like can be used. Of these, silica gel and zeolite also have the effect of removing HC,
It is preferable because it can be recycled and can be used for a long period of time.

The water concentration in the gas to be treated is 50% (RH:
Dehumidifying to a relative humidity) or less, preferably 30% (RH) or less improves the HC adsorption performance of the adsorbent and maintains the performance stably for a long time. The dehumidification method and the limiting moisture concentration can be determined by conducting a preliminary test as appropriate depending on the type and scale of the applied device, the type of HC removing material, the required performance, the economical efficiency and the like. Generally, when dehumidifying is performed, the HC removing performance of the adsorbent is stably maintained for a long period of time. In particular, the performance is remarkably stable when a hydrophobic substance such as silica gel or a fluorine compound is used as the adsorbent. On the other hand, the dehumidification can be omitted when the dehumidification amount may be small or when the water concentration of the gas to be treated is low. That is, the dehumidification can be determined by appropriately performing a preliminary test depending on the type of adsorbent, the field of use of the device, the water concentration in the gas to be treated, the scale and shape of the applied device, the required performance, the economical efficiency, and the like.

In using the adsorbent, PSA (pressure swing adsorption) is used in addition to the above-mentioned usage (with dehumidification).
It is possible to regenerate the adsorbent at the same time by TSA (heat swing adsorption). As the HC absorbent, any material can be used as long as it can react with low concentration HC and immobilize it. Generally, a reaction with Cr ⁶⁺ in the coexistence of H ₂ SO ₄ or a reaction with I ₂ O ₅ in the coexistence of H ₂ S ₂ O ₇ can be used. The former is effective for low molecular weight HC and the latter is effective for high molecular weight HC. For example, the surface of a carrier such as glass beads or an appropriate shape (for example, a pellet) of zeolite or alumina is impregnated with an aqueous salt solution containing H ₂ SO ₄ acidic hexavalent chromium. The term "absorption" means that the reaction is absorbed by a chemical reaction.

The usage conditions of the adsorbent and / or the adsorbent can be determined by conducting preliminary tests as appropriate according to the application field of the device of the present invention, the scale of the device, the shape, the required performance and the like.
The space velocity (SV) of the air to be treated in the device is usually 100-
20000 (h ^-1 ), preferably 100 to 5000 (h
^-1 ). Next, irradiation of ultraviolet rays and / or radiation will be described. The H. The processing of C is proposed by the present inventor (Japanese Patent Application No. 3-22686, Japanese Patent Application No. 3-105).
No. 092) can be appropriately used. By irradiation with ultraviolet rays and / or radiation, H. C. H.
C. Depending on the type and coexisting substance, it is converted into a fine particle substance (condensable substance) or a fine particle substance and an active substance.

For example, H.264. C. When a gas mixture containing toluene, alkane (i-pentane) and olefin (propylene) is irradiated with ultraviolet rays as described above, carboxylic acid or carbonyl compound (condensable substance or active substance) is produced. 260n for conversion to fine particles
Irradiation sources having a wavelength of m or less, preferably 245 nm or less are effective. The ultraviolet ray source causes H.
C. Can be made into fine particles (converted to fine particles or a condensable substance or converted to fine particles and an active substance). C. It can be decided by conducting a preliminary test as appropriate depending on the type and coexisting substance. Among these, those that generate oxygen active species (active radicals) such as active oxygen and OH radicals are preferable depending on the field of use.

Generally, a mercury lamp or a hydrogen discharge tube (deuterium lamp) can be used as the light source of ultraviolet rays. The light source of ultraviolet rays is H.264. C. Those having a plurality of wavelengths that bring about different actions are preferable depending on the type and coexisting substance.
For example, a mercury lamp is preferable because it can have both a wavelength of ozone generation (one of the starting materials for generating oxygen active species) and a wavelength that decomposes the ozone and promotes generation of oxygen active species. As radiation, α rays, β rays,
A method in which γ-rays are used, and radioactive isotopes such as cobalt 60, cesium 137, and strontium 90 are used as irradiation means, or radioactive waste produced in a nuclear reactor and radioactive materials appropriately processed therefor are used as a radiation source. ,
A method using a nuclear reactor as a direct radiation source, a method using a particle accelerator such as an electron beam accelerator, and the like are used.

When the electron beam irradiation is performed by the accelerator, high-density irradiation can be performed effectively by performing the irradiation with a low output. The acceleration voltage is 500 kV or less, preferably 50 kV to 3
It is 00 kV. In the irradiation, H. C. Depending on the type and coexisting substance, fine particles (condensable substance) can be generated by the above irradiation.
Or into a particulate substance and an active substance (highly reactive substance), and converted into a form that can be easily handled (processed). The particulate matter or active substance thus produced is already proposed by the present inventor to be charged and collected and removed by photoelectrons (eg, Japanese Patent Publication No. 3-585).
No. 9, JP-A-2-303557) and known filters or adsorbents can be used for collection and removal.

Further, it can be treated by bringing it into contact with a complex oxide catalyst which has already been proposed by the present inventor and has ozone decomposing ability and ability to adsorb harmful substances (Japanese Patent Application No. 4-332).
167). The fine particles are generally ultrafine particles. The particle size of fine particles generated from ordinary hydrocarbons is 0.01 to 0.0
It is about 5 μm, and as described above, the fine particles have a feature that they are higher in activity than ordinary fine particles (eg, an inorganic substance) or coexist with an active substance. Any filter may be used as long as it can collect the above-mentioned fine particles, and generally, a filter of a filtration system, for example, a HEP filter, a ULPA filter, an electrostatic filter, a filter using an electret material, an ion exchange filter (fiber) is used. Can be usually in this HEP filter, ULP
The A filter and the ion exchange filter are preferable because they are simple and highly effective.

In particular, the ion exchange filter is preferable because it is highly effective in collecting and removing active substances as described above. Depending on the field of use, an adsorbent such as activated carbon can be used as appropriate. An adsorbent such as activated carbon is preferable in some fields of application because it can collect coexisting active substances and harmful gases as in the ion exchange filter. Whether to collect and remove fine particles by applying charge by photoelectrons, or by using an adsorbent or a filter should be appropriately selected depending on the application field, device scale, shape, effect, economical efficiency, or a combination thereof. You can

The above has described the embodiment of the present invention in the case of removing extremely low concentration HC in various gases used in a clean room such as normal air, nitrogen, and argon. In general, substances that contaminate the base material or substrate surface of conveyed products and increase the contact angle are (1) SOx, NOx, HC
1, harmful gas such as NH ₃ , (2) fine particles, (3) H
As a result of a study by the present inventor, the contact was observed in normal air (environmental air in a normal clean room) or N ₂ used in a clean room such as a semiconductor manufacturing factory or a liquid crystal manufacturing factory. The influence of fine particles and HC on the corners is great. That is, generally SOx, NOx, HC
l and NH ₃ have little effect on the increase of the contact angle at normal concentration levels in air. Therefore, the effect is obtained by removing dust and HC.

However, when harmful gases such as SOx are generated in or around the clean room and their concentrations are high, they are affected by these gas components, and even when these concentrations are so low that they do not usually affect them. However, it may be affected when the base material or the substrate is sensitive or in a special state (for example, when the surface of the base material is coated with a special thin film). In such a case, another well-known harmful gas removing material such as activated carbon or ion exchange resin may be appropriately combined and used. Activated carbon may be one that is impregnated with an acid or an alkali, or is appropriately modified by a known method.

The HC component in the air is said to be a mixture of hundreds or thousands of components. Which of these various HC components is involved in increasing the contact angle and to what extent? Unknown. Therefore, there are many unclear points about the mechanism for preventing the increase of the contact angle by the HC removing means, but it is considered as follows. That is, it is estimated that substances having particularly large molecular weight and substances having high activity among the HC components have a large influence on the increase of the contact angle, and these substances are effectively adsorbed and collected by the HC removing means.

The above has described the collection and removal of pollutants against the contamination of the conveyed product, and the medium is air.
Any gas such as nitrogen or argon can be suitably applied. In the present invention, as described above, in addition to the dust removing action, the contact angle increasing preventing action, the static electricity removing action by the irradiation of ultraviolet rays and / or radiation and the generated photoelectrons are added, and therefore, a preferable effect is obtained depending on the application field / apparatus. Regarding static elimination (neutralization), another proposal of the present inventor (Japanese Patent Application No. 4-216623).
No.), it can be used as appropriate for static elimination conditions.

Any type of medium in the closed space can be preferably used in terms of removing contaminants as described above. Also, depending on the field of use and type of equipment, when performing the above-mentioned collection / removal of pollutants and significant static elimination of conveyed products, static electricity can be eliminated by using nitrogen as a medium and short wavelength ultraviolet rays or soft X-rays. It is preferable because they can be remarkably performed, and these can be appropriately used. As described above, the photoelectron emitting material that can be used in the present invention, the irradiation of ultraviolet rays and / or radiation, the electrode material, the means for collecting and removing non-methane hydrocarbons, the type and use conditions of the medium gas, etc. Equipment type, scale, shape, required performance, environmental conditions,
It can be decided by conducting a preliminary test as appropriate depending on the economical efficiency.

[0044]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto. Example 1 FIG. 1 shows a semiconductor device manufacturing apparatus in a class 10,000 clean room in which a transfer device 1 for transferring a wafer from step A to step B is provided with a wafer stocker 2 between steps A and B. .

FIG. 2 is a sectional view of the carrier device 1.
Referring to FIG. 2, the photoelectron emitting material of FIG. 2 uses a bulk (Cu-Zn or less Au plating) photoelectron emitting material. The transfer device 1 includes a drive device 4 for transferring the wafer 3, an ultraviolet lamp 6 for collecting and removing fine particles (particulate matter) 5 accompanying the wafer entrained fine particles and the driving of the transfer device, Photo-emissive material 7,
It is composed of an electrode 8 and an ultraviolet reflecting surface 9.

The fine particles 5 are charged by the photoelectrons 10 emitted from the ultraviolet light emitted from the ultraviolet lamp 6 to the photoelectron emitting material 7 to become charged fine particles 11, which are charged fine particles 11.
Are collected by the electrode 8. In this way, the vicinity of the wafer 3 in the transfer device 1 is highly cleaned, so that the contamination of the wafer is prevented. Here, the electrode 8 has a function of an electrode (+ pole) for irradiating the photoelectron emitting material (-pole) 7 with an ultraviolet ray under an electric field, and a function as a collector of charged fine particles. 1
Reference numeral 2 is a transparent window for ultraviolet rays, which is a quartz glass window.

FIG. 3 shows a stocker 2 integrated in the transport apparatus of FIG. The stocker 2 is a charging / collecting unit I for fine particles.
And the wafer stock section II. The fine particle charging / collecting section I is composed of an ultraviolet lamp 6, a photoelectron emitting material 7 in which quartz glass is coated with a thin film of Au, an electrode 8, and an ultraviolet reflecting surface 9, and a fine particle 5 in the stock portion II (space to be cleaned). Move to the charging / collecting section I due to a diffusing force, etc., and are charged by the photoelectrons 10 emitted from the photoelectron emitting material 7 to become charged fine particles 11. The charged fine particles 11 are collected by the electrode 8 and the stock portion of the wafer. In II, a clean space higher than Class 1 is maintained. Reference numeral 15 denotes a light shielding material for preventing direct irradiation of the wafer in the stock portion of ultraviolet rays. 1
3 is a wafer, and 14 is a wafer carrier.

In semiconductor manufacturing, a wafer is usually transferred from the process A to the process B, and then the product is completed through processes C and D (not shown). Here, in the event of an emergency during transportation from the process A to the process B, for example, when a trouble or problem occurs after the process B, or when it is desired to finish the operation on the weekend (Friday) in the process A, the transport device provided before the process B is used. The wafers being transferred from the process A to the process B are stocked in the integrated stocker 2. Then, after an appropriate time, the wafer is sent from the stocker 2 to the transfer section of the transfer device and transferred to the step B.

Example 2 FIG. 4 shows another embodiment of the conveying apparatus of Example 1. Figure 4
Is a photoelectron emission material 7 in which quartz glass is coated with a thin film of Au, and the electrode 8 is located on the opposite surface of the transport space. Each symbol is the same as that of the first embodiment and the same symbol has the same meaning.

Example 3 FIG. 5 shows another embodiment of the conveying apparatus of Example 1. Figure 5
Is a photoelectron emission material 7 in which quartz glass is coated with a thin film of Au, the electrode 8 is located in the vicinity of the photoelectron emission material 7, and a light shielding material 15 is further installed so that the wafer is not directly irradiated with ultraviolet rays. . This transfer device is suitable when the transferred product has a sensitive (active) substrate or substrate surface. Each symbol is the same as that of the first embodiment and the same symbol has the same meaning.

Example 4 FIG. 6 shows another embodiment of the conveying apparatus of Example 1. Figure 6
Is a product in which the surface of the ultraviolet lamp 6 is coated with a photoelectron emitting material Au in a thin film form 7, the ultraviolet lamp 6 and the photoelectron emitting material 7 are integrated, and a light shielding material 15 is further installed. Each symbol is the same as that of the first embodiment and the same symbol has the same meaning.

Example 5 FIG. 7 shows a case in which wafers are transferred in a class 10,000 clean room in Example 1 in an air-cooled atmosphere from which non-methane hydrocarbons have been removed. Hereinafter, this example will be described in detail. Outside air 10 before entering the clean room 100
1 is first processed by the coarse filter 102 and the air conditioner 103. Next, when the air enters the clean room 100, it is dust-removed by the HEPA filter 104, and air having a concentration of class 10,000 in which extremely low concentration of HC coexists 1
It will be 05. That is, the extremely low concentration HC mainly generated from the automobile is not removed by the coarse filter 102, the air conditioner 103, and the HEPA filter 104, and therefore is introduced into the clean room 100. The concentration of HC in the air 105 is 0.5 to 0.8 ppm for non-methane HC.

The air 105 in the clean room 100 containing water (RH 40 to 60%), fine particles (class 10,000) and extremely low concentration of HC is first dehumidified by a dehumidifier (dehumidifier) 106 to a certain concentration or less. To be dehumidified. The dehumidifier of this example is based on the electronic dehumidification system,
The humidity in the clean room 100 (RH40-60
%) Is less than 30%. The dehumidified air is then used as the HC adsorbent, that is, the gas adsorption / removal device 10
7 to remove very low concentrations of HC. The HC adsorbents 108 and 109 may be any as long as they remove the extremely low concentration of HC normally present in the atmosphere.

In this example, silica gel 108 as the adsorbents 108 and 109, a fibrous glass material formed into a filter shape by using a fluorine compound resin as a binder, 109
Are using. As a result, the non-methane HC in the air is removed to a concentration of 0.1 ppm or less. The air whose methane HC is 0.1 ppm or less is introduced from the front of the transfer device 1, and the space where the wafer of the transfer device 1 is present and the space of the stocker 2 become the atmosphere of the air. If the wafer is exposed to the air atmosphere, the contact angle can be prevented from increasing, so that the film formation in the next step B can be firmly and strongly formed (with a large adhesive force) on the wafer.

Embodiment 6 FIG. 8 shows a case where the air is replaced with nitrogen in the embodiment 5 and the wafer is transferred (the wafer is transferred in a nitrogen atmosphere). In FIG. 8, reference numeral 110 is a nitrogen supply device, and the nitrogen 110 is removed by the gas adsorption device 107 to a concentration of 0.1 ppm or less of non-methane HC in nitrogen as in the fifth embodiment. The same symbols as those in Example 5 have the same meanings.

The ultraviolet ray source in the carrying device 1 and the stocker 2 of this example is a deuterium lamp, and the static elimination effect remarkably occurs. That is, in this example, the fine particles have a remarkable static elimination effect in addition to the HC removal. When the supplied nitrogen is dry (water concentration is 30% RH or less), the dehumidifier 106
Is unnecessary (although it is usually unnecessary), the dehumidifier 106 is installed here in consideration of the mixing of water.

Example 7 A class 1 transport apparatus in which the stocker of Example 1 is integrated
The operation was carried out in a clean room of 10,000, and the number of adhered particles (particle diameter: 0.2 μm or more) on the wafer surface was examined in the case where charge collection of fine particles by photoelectron emission was present or not. 1) Conditions of transfer section (Particle charging / collection sections by photoelectron emission are installed at five locations in the transfer device at equal intervals) Wafer: 5-inch wafer manufactured by A. Wafer transfer method: robot method Transfer length: 2 m UV lamp : 3 W of germicidal lamp Photoemissive material: Cu-Zn material plated with Au Electrode: Cu-Zn material plated with Au Electric field strength: 50 V / cm

2) Conditions of stocker part Size: 60 liters Ultraviolet lamp: Sterilization lamp 10W, 3 pieces Photoelectron emitting material: Quartz glass with ITO 50Å and Au 50
Å coating Electrode: Au-plated Cu-Zn (lattice) Light-shielding material: Au-plated Cu-Zn plate (staggered) (light-shielding material used as -pole and photoelectron emission function) Electric field strength: 50V / cm The number of adhered particles on the wafer surface was measured by a laser beam type wafer and a dust detection device (WM-3, manufactured by TOPCON).

Results Results are shown as average values of 10 wafers. (1) When the number of particles deposited on the initial wafer was 6 and the number of particles deposited on the wafer at the exit was examined, it was 6. As a comparison, when the ultraviolet lamp and the electric field were turned off, the wafer was similarly transported by the transport device, and the number of particles deposited on the wafer at the exit was examined. As a result, there were 26 wafers with initial deposition particles at the exit. It was

(2) The number of adhering particles on the wafer was 8 when the wafers (the number of particles on the initial wafer: 7) in the above-mentioned transportation were put in the stocker for 2 days and taken out after 2 days. As a comparison, the wafer at the exit of the transfer device (1) (the number of adhered particles on the wafer is 6) was left on a clean bench of class 1,000 for 2 days, and the number of adhered particles on the wafer was examined in the same manner after 2 days. Met.

Example 8 The contact angle (the number of adhered particles) on the wafer was examined in the case where the wafer was transferred in the atmosphere of air from which the non-methane hydrocarbon was removed in Example 5. 1) Conditions of the transport section (five particles are charged / collected by photoelectron emission at equal intervals in the transport system) Non-methane hydrocarbon removing material: Fibrous glass material with silica gel and fluorine compound resin as binder Combination of. Air velocity to non-methane hydrocarbon removal material: SV 1.00
0 (h ^-1 ) Wafer: 5-inch wafer manufactured by A. Wafer transfer method: robot method Transfer length: 2 m Ultraviolet lamp: germicidal lamp 3 W, 3 photoelectron emission materials: Cu-Zn material plated with Au Electric field strength : 50V / cm

2) Stocker conditions Size: 60 liters Ultraviolet lamp: Sterilization lamp 10W, 3 photoelectron emitting materials: Quartz glass with ITO 50Å and Au 50
Å coating Electrode: Au-plated Cu-Zn (lattice) Light-shielding material: Au-plated Cu-Zn plate Electric field strength: 50 V / cm The number of adhered particles on the wafer surface is a laser beam type wafer / dust The contact angle was measured with a detection device (WM-3, manufactured by TOPCON), and the contact angle was measured by a droplet type contact angle meter (CA-D type, manufactured by Kyowa Interface Science Co., Ltd.).

Results Results are shown as the average value of 10 wafers. (1) An initial wafer number of adhered particles: 6, a contact angle: 11 degrees, was placed in a transfer device, and the number of adhered particles on the wafer at the exit and the contact angle were examined.
It was degree. As a comparison, when the same operation was performed with air in which non-methane hydrocarbons were not removed, the number of initial adhered particles: 6,
A wafer having a contact angle of 11 degrees had a number of adhered particles of 6 at the outlet and a contact angle of 16 degrees.

(2) Two wafers (the number of particles adhered on the initial wafer: 6 and a contact angle: 11 degrees) being transferred are put in the stocker 2
It was put in for one day and taken out after two days. Similarly, the number of adhered particles and the contact angle on the wafer were examined. As a result, the number of adhered particles was 6 and the contact angle was 12
It was degree. As a comparison, the wafer at the exit of the transfer device of the above 1 (number of adhered particles on wafer: 6, contact angle: 11 degrees) was left on a clean bench of class 1,000 for 2 days, and contacted with the number of adhered particles on the wafer after 2 days. When the angles were examined, the number of adhered particles was 398 and the contact angle was 45 degrees.

[0065]

According to the present invention, the following effects can be obtained. (1) By providing at least a photoelectron emitting material, an ultraviolet ray and / or a radiation source, and an electrode in the transfer device, particles in the transfer space, for example, particles entrained in a transfer product (eg, wafer, liquid crystal), or a drive unit for transfer Since the fine particles (particulate matter) generated from the above are charged and collected, the transport space is kept highly clean. The static elimination effect could be added depending on the short wavelength ultraviolet ray and / or radiation irradiation conditions. Due to the above, the contamination of the conveyed product was eliminated and the yield was improved.

(2) By integrating a stocker having at least a photoelectron emitting material, an ultraviolet ray source and / or a radiation source, and an electrode with the carrying device, the goods to be carried can be stocked without being exposed (exposed) to the outside. (Transported goods could be maintained in a highly clean state). After an appropriate (arbitrary) time, it could be conveyed to the next step in a highly clean state. Yield improved.

(3) In the transfer device, the hydrocarbons in the gas which come into contact with the transferred product are set to 0.
By removing up to 2 ppm or less, it was possible to prevent an increase in the contact angle of the conveyed product. The yield of transported products has improved. (4) In 1 to 3, short wavelength ultraviolet rays (1
When using soft X-rays as a radiation source, a static elimination effect is remarkably added to the dust removal effect, which is preferable in some fields of use. In particular, in the case of short-wavelength ultraviolet light, it is preferable to use nitrogen as a gas depending on the field of use because it is effective.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a transfer device including a stocker.

FIG. 2 is a cross-sectional view of the transfer device of the present invention.

FIG. 3 is a sectional view of the stocker in FIG.

FIG. 4 is a cross-sectional view of another conveyance device of the present invention.

FIG. 5 is a cross-sectional view of another conveyance device of the present invention.

FIG. 6 is a cross-sectional view of another transfer device according to the present invention.

7: H. C. The schematic explanatory drawing of the clean room provided with the removal device.

FIG. 7: H.V. performed with nitrogen gas C. The schematic explanatory drawing of the clean room provided with the removal device.

[Explanation of symbols]

1: carrier device, 2: stocker, 3, 13: wafer, 4:
Driving device, 5: fine particles, 6: ultraviolet lamp, 7: photoelectron emitting material, 8: electrode, 9: ultraviolet reflecting surface, 10: photoelectron,
11: charged fine particles, 12: transmission window, 14: wafer carrier, 15: light-shielding material, 100: clean room, 101:
Outside air, 102: Coarse filter, 103: Air conditioner, 10
4: HEPA filter, 105: air, 106: dehumidifier, 107: gas adsorption / removal device, 108: silica gel,
109: Fluorine compound resin filter, 110: Nitrogen

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[Procedure amendment]

[Submission date] January 13, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a transfer device including a stocker.

FIG. 2 is a cross-sectional view of the transfer device of the present invention.

FIG. 3 is a sectional view of the stocker in FIG.

FIG. 4 is a cross-sectional view of another conveyance device of the present invention.

FIG. 5 is a cross-sectional view of another conveyance device of the present invention.

FIG. 6 is a cross-sectional view of another transfer device according to the present invention.

7: H. C. The schematic explanatory drawing of the clean room provided with the removal device.

FIG. 8 is a diagram showing an H. C. The schematic explanatory drawing of the clean room provided with the removal device.

[Explanation of Codes] 1: Transfer device, 2: Stocker, 3, 13: Wafer, 4:
Driving device, 5: fine particles, 6: ultraviolet lamp, 7: photoelectron emitting material, 8: electrode, 9: ultraviolet reflecting surface, 10: photoelectron,
11: charged fine particles, 12: transmission window, 14: wafer carrier, 15: light-shielding material, 100: clean room, 101:
Outside air, 102: Coarse filter, 103: Air conditioner, 10
4: HEPA filter, 105: air, 106: dehumidifier, 107: gas adsorption / removal device, 108: silica gel,
109: Fluorine compound resin filter, 110: Nitrogen

Claims (4)

[Claims] 1. A carrier device having a hermetically sealed space, wherein a gas cleaning means having a photoelectron emitting material, an ultraviolet ray source and / or a radiation source and an electrode is provided in the space. 2. The transfer device according to claim 1, wherein a part of the sealable space is a stocker. 3. The gas in the sealable space is adsorbed,
The transport apparatus according to claim 1, wherein the gas is purified by one or more kinds of means selected from absorption, ultraviolet ray and / or radiation irradiation. 4. The transfer device according to claim 1, wherein the gas in the sealable space is nitrogen.