JP2678367B2 - Steam cleaning equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for removing either or both of organic contaminants and deposits on the surface of an article, and more particularly to a vapor cleaning apparatus for the surface of a semiconductor wafer.

[Conventional technology]

Semiconductor elements such as diodes and transistors are formed on the surface of a semiconductor wafer, and when they are integrated, they become semiconductor integrated circuit elements, which are important components of advanced technological products at the center of semiconductor industry electronics.

A semiconductor wafer is mainly composed of a high-purity silicon wafer (hereinafter simply referred to as a silicon wafer). When a diode or a transistor is formed on this surface, the semiconductor properties of the silicon wafer must be effectively used. The crystal quality of the bulk and various impurities, as well as the crystal quality of the surface and the presence of various impurities have serious influences. In recent semiconductor device manufacturing technology, it is desired that the crystal quality is as perfect as possible and the impurities are as small as possible, except that bulk crystal defects and impurities are utilized as an internal getter effect.

In particular, the removal of impurities on the surface of the silicon wafer and the improvement of the crystal quality are indispensable for improving the performance of semiconductor devices, and improving the yield and cost in industrial production. In the recent era in which the degree of integration is remarkably improved, the demand for the surface quality of a silicon wafer, which is a substrate for an integrated circuit semiconductor device, becomes more severe and precise.

Contamination on the surface of a silicon wafer can be classified into ionic contamination and non-ionic contamination, depending on the separation method, as long as there is one line. The former is caused by chemical cleaning with acid / alkali in the manufacturing process of silicon wafers, contact during processing of parts of processing equipment and untreated tap water or groundwater used carelessly, while the latter is mainly organic pollution. Occurs from contact with plastics such as wax, oil and handling.

It is particle contamination that should be noted for organic and inorganic contamination, because of insufficient removal of the polishing agent in the processing process, especially in the polishing process, generated from the human body, brought in from pure water of chemicals, or It is carried in together with the air for air conditioning and adheres to the surface of the silicon wafer. This particle contamination can be organic or inorganic.

Since various surface stains adhere to the surface of the silicon wafer as described above, various cleaning methods have been devised to remove them. For example, (1) in order to remove organic matter, treatment with an organic solvent, a surfactant, etc., treatment with an acid / alkali (both may use an oxidizer together), or in addition to these, washing with a brush is performed, ( 2)
Hydrofluoric acid treatment to remove oxide film (Natural Oxide, etc.), (3) Treatment with acid or alkali to remove metal impurities and ionic impurities, and use oxidizer together to oxidize metal impurities Sometimes. (4) Ultrasonic brush water washing is performed to remove particulate impurities,
(5) Hydrofluoric acid treatment for removing the oxide film, (6) washing with water, and (7) drying.

In the cleaning process, a kind of chemical treatment is performed on the surface, so that a surfactant, ultrasonic waves, stirring, etc. are effectively used in each process in order to prolong the contact between the treatment agent and the wafer.

High-purity water is a basic cleaning agent for silicon wafers because it is economically inexpensive, has no pollution problems, and is easily available. Therefore, ultrapure water is always used in a large amount in the final step or the substantial final step.

The slight amount of water remaining on the surface of the silicon wafer will spontaneously evaporate if it is of extremely high purity, so there should be no problem.
Since the atmosphere in which a silicon wafer is stored is not usually an ideal clean atmosphere, dust or gas in the atmosphere is captured or dissolved in the water droplets on the silicon wafer, and the dissolved substances from the dust or gas are evaporated into a film after the water droplets evaporate. There is also a case where the dust adheres to the surface and becomes a stain, and the dust itself is firmly bonded, which makes it difficult to remove it in the subsequent washing step. For this reason, the silicon wafer washed with ultra-high purity water must be dried and stored immediately.

Furthermore, organic substances should be completely removed from the silicon wafer that has been washed with ultra-high-purity water.However, the work environment space should be generated from the rotating parts of the machine or oil mist that is carried in together with the external air, or a clean room. There are a lot of organic substances that are generated from organic materials such as sealing materials, equipment used, paints, etc., which inevitably adhere to the surface of silicon wafers. Therefore, in case the organic substances are not completely removed, the final step requires a drying method effective for removing the organic substances.

For this reason, the steam cleaning method is often used for the final finishing of silicon wafers.

In the steam cleaning method, an organic solvent having relatively good volatility at room temperature is boiled at the bottom, the steam is brought into contact with the object to be cleaned, and the space around the object to be cleaned is cooled by the heat capacity of the object to be cleaned or a cooling coil. , It liquefies the vapor and covers the surface of the object to be cleaned with the liquefied vapor to remove water and residual organic matter with dropping, but in the conventional vapor cleaning method, the liquefied vapor contaminated by the vapor cleaning is directly on the bottom. When the silicon wafer is cleaned by the steam cleaning method, the cleanliness after cleaning the surface of the silicon wafer is used as the steam source. The organic solvent used was significantly deteriorated with the lapse of time, and many stains were not seen on the surface before the start of steam cleaning, and some improvement was desired.

As a steam cleaning device for improving the above problems, for example, Japanese Patent Publication No. 59-39162 discloses at least a dehydration tank, a boiling tank, a steam tank, a main body having a condenser, and a cooling water removing section, which are produced by the condenser. An apparatus has been proposed in which the condensate is guided to a cooling and water removing section, and after cooling and removing water, ethanol-containing trichlorotrifluoroethane returned to the boiling tank is used as a cleaning solution to wash and dry the article. The improvement in this device is that the vapor condensate is not directly introduced into the boiling tank but is introduced into the cooling water removal section, where the aqueous ethanol solution is separated from trichlorofluoroethane in a liquid state, and then only trichlorofluoroethane is circulated to bring it to a boiling state. Washing should always be water unsaturated. It is believed that this completely dehydrates the surface of the object to be cleaned.

The apparatus described in the above publication has a problem in that the composition is controlled because two kinds of organic solvents are used, and thus the equipment cost is high. Further, the apparatus described above covers the surface of the washing object and stains it. The liquefied cleaning liquid, which is dropped after being dissolved, returns to the boiling liquid as it is, raises the water concentration in the boiling liquid, and is not contaminated with organic substances or the like.

Next, a one-pack type vapor cleaning device using isopropyl alcohol will be introduced as another conventional device. In this case, for example, as shown in FIG. 4, a semiconductor wafer (hereinafter referred to as “wafer”) is housed in the upper part of the processing housing as the vapor cleaning target 1, and the volatile liquid in the tank provided in the lower part of the processing housing is removed. Steam is generated by heating and the wafer is steam-cleaned with this steam.

In Fig. 4, this steam cleaning device (cleaning / drying machine)
Is provided with a space F containing an object to be steam-cleaned, and a container 6 for containing a cleaning liquid is provided at the bottom of the space F. The container 6 contains, for example, isopropyl alcohol (hereinafter, IP
A) is stored.

This IPA is heated by a steam generator 5 which is a liquid heating bath provided at the bottom of a container 6 to generate steam 9. A cooling pipe 8 is laid in an annular shape in the upper part of the space F containing the object to be cleaned with steam, and when the steam 9 is cooled by this pipe 8, the steam 9 condenses into dew-like drops and drops. Recovered in 10.

When the steam cleaning target 1 in a wet state, for example, a wafer is carried into the space F of such a steam cleaning device while being held by the work holder 2, the cleaning adhered to the wafer is cleaned. Moisture and residual organic matter in the process are
It is dissolved in the liquefied vapor and becomes a drain, which is dropped on the drain recovery pan 4 installed below the vapor cleaning target 1. Then, the drain on the drain recovery pan 4 is discharged to the outside through the discharge pipe 20.

[Problems to be solved by the invention]

However, in the structure of the steam cleaning apparatus shown in FIG. 4, since the drain recovery pan 4 is directly heated by the steam 9, the surface temperature of the drain recovery pan 4 becomes approximately equal to the boiling point of the cleaning liquid.

Therefore, re-evaporation of the condensate recovered in the drain recovery pan 4 occurs, and contaminated water contained in the drain at this time,
Impurities such as dirt diffuse and float in the space F, causing a problem that the steam cleaning target object 1 located above is soiled again.

Further, the re-evaporated vapor from the recovered condensate from the drain recovery pan 4 mixes with the vapor from the container 6 containing the cleaning liquid,
Since these mixed vapors contain a large amount of water, in an extreme case, water separation occurs in the liquid film on the surface of the object 1 to be cleaned. When the object to be cleaned 1 is taken out to the outside from the upper part of the main cleaning device after a certain amount of steam cleaning, the cleaning liquid on the surface is instantaneously volatilized and the surface of the object to be cleaned 1 is exposed. Is contaminated due to residual moisture, resulting in incomplete steam cleaning.

It should be noted that reducing the temperature of the drain recovery pan 4 to cope with this problem makes effective steam cleaning impossible because the steam 9 condenses at the location of the drain recovery pan 4.

INDUSTRIAL APPLICABILITY The present invention provides a steam cleaning apparatus for removing surface organic contaminants and adhered water of articles, and particularly effective for residual organic contaminants and adhered water after cleaning the surface of a semiconductor substrate for integrated circuit elements with ultra-high purity water or the like. The purpose is to completely eliminate the drawbacks of the conventional vapor cleaning apparatus, improve the cleaning of the surface on the semiconductor wafer, and reduce the cleaning cost by using the economical apparatus. To do.

[Means for solving the problem]

In order to solve the above-mentioned problems, the present invention provides a cleaning space for accommodating an object to be cleaned, a container under the cleaning space for accommodating the cleaning liquid, and a cleaning liquid in the container is heated to evaporate by evaporation. A steam generator for causing the steam generated from the cleaning liquid to come into contact with the surface of the object to be cleaned, thereby adhering water on the surface of the object to be cleaned and / or
Alternatively, in a steam cleaning device for removing organic contaminants, a drain recovery pan for recovering a liquefied cleaning liquid with an open top is provided in the cleaning space, and the drain is provided by the cleaning liquid storage container and the steam generator. Surrounding the recovery pan, the temperature control means for maintaining the surface temperature of the drain recovery pan at a temperature 5 to 10 ° C. lower than the boiling point of the cleaning liquid and lower than the azeotropic point of the cleaning liquid and water, and the drain recovery pan. Provided is a steam cleaning device characterized by being provided with a discharge pipe for discharging drain inside thereof to the outside, and further, Freon 113, methylene chloride, 1,1,1-
The present invention proposes a vapor cleaning device characterized by using any one of trichloroethane, isopropyl alcohol, and chloroform.

[Action]

The steam cleaning method is a method devised for cleaning the surface of an article by removing organic substances or attached water on the surface of the article. As the vapor source, one liquid is usually used, and a water-soluble organic solvent is mixed and used especially when adhering water has to be removed. Such a two-component type is effective when organic matter stains and adhered water on the surface of the article are attached so that they can be detected by the naked eye, but in the case of the semiconductor wafer as in the present invention, since the stain is less. , If a water-soluble organic solvent is included, the control of the liquid composition becomes complicated, and for other reasons, if it is a two-liquid type, it is easily contaminated, and it is easy to absorb water from the air, and the composition changes easily. There is harm. Usually, an organic solvent which is said to be insoluble in water always dissolves a little water in a high temperature liquefied state, and is therefore sufficient for cleaning a semiconductor wafer.

The semiconductor wafer comes into contact with the vapor of the volatile organic cleaning liquid rising from below, and liquefaction occurs on the surface of the semiconductor wafer at the beginning, and this liquefied vapor film dissolves the residual trace organic matter and / or adhering water on the surface of the semiconductor wafer and fluidizes it. , Drop down separately. However, the temperature of the semiconductor wafer rises with the passage of time, and the liquefaction on the surface of the semiconductor wafer decreases with it, and the cleaning liquid is cooled and condensed by a water-cooled serpentine pipe provided inside the wall of the device surrounding the semiconductor wafer of the steam cleaning device. The mist covers the entire semiconductor wafer and is condensed on the surface to form a liquid film. In this equilibrium state, the temperature of the semiconductor wafer is also raised close to the vapor temperature, and the organic matter and adhered water on the surface of the semiconductor wafer are effectively dissolved and removed.

In the present invention, since the drain recovery pan is surrounded by the cleaning liquid storage container as the steam generation tank and the steam generation device as the heating source for heating the container, the cleaning target is the drain recovery pan of the drain recovery pan. By arranging almost directly above, the steam generated evenly from the entire container for the cleaning liquid flows smoothly toward the object to be cleaned (that is, from the outer peripheral portion to the central portion of the vapor cleaning device).

In this case, since the drain recovery pan is provided in the lower part of the cleaning space for accommodating the object to be cleaned, the vapor of the cleaning liquid flows toward the object to be cleaned while avoiding the drain recovery pan. The surface temperature of the is not raised to a temperature at which the drain in the recovery pan evaporates. Also,
Normally, the drain of the cleaning liquid vapor and the azeotropic mixture of the cleaning liquid and water are collected in the drain recovery pan as the drain, but the surface of the drain recovery pan is 5-10 ° C lower than the boiling point of the cleaning liquid by the temperature control means. In addition, since the temperature is maintained at a temperature lower than the boiling point (azeotropic point) of the azeotropic mixture, re-evaporation of the drain can be reliably prevented, and the cleaning liquid vapor supplied to the cleaning target is the drain recovery pan. The rate of condensation in the vicinity can be suppressed to an extremely low level, and the cleaning liquid vapor can be supplied with good thermal efficiency.

Therefore, the condensate on the surface of the object to be cleaned is kept in unsaturated water, and as described above, the adhered water on the surface of the object to be cleaned can be well dissolved and the organic matter can be well dissolved.

In addition, since the drain does not return to the container for storing the cleaning liquid at all, the liquid composition is not contaminated with organic substances and water, and the pure cleaning liquid vapor is always used as the cleaning object 1.
Will wet the surface of.

As the cleaning liquid, Freon 113, methylene chloride, 1,1,1-
Volatile liquids such as trichloroethane, isopropyl alcohol and chloroform can be used. The higher the boiling point, the less the escape from the upper opening of the steam cleaning device, the better the recovery rate, and the higher the cleaning effect because the object to be cleaned is heated at high temperature. However, if the temperature is too high, it is necessary to keep the temperature of the side part of the cleaning device and special heating device of the steam generator is required. Considering the handling at room temperature and the temperature rise of the object to be cleaned, the lower limit of the boiling point should be set to about 40 ° C. For the purpose of the present invention, the compatibility with water is only required to be a little, and the above-mentioned organic solvent can be used for dehydration of the object to be cleaned without any problem. Next, the boiling point (BP) of each organic solvent, the azeotropic point with water, and the composition (concentration of the organic solvent) are shown.

[Examples] The present invention will be described below with reference to the examples shown in the drawings. FIG. 1 is a vertical sectional view showing an embodiment of a steam cleaning apparatus according to the present invention, and FIG. 2 is a sectional view taken along the line AA ′ of FIG.

As shown in FIG. 1, the steam cleaning apparatus of the present invention has a space F containing a steam cleaning target and a vapor generation tank E. At the center of the space F, a work holder 2 holds a vapor cleaning target 1, for example, a silicon wafer. A drain recovery pan 4 is provided in the lower part of the work holder 2, and a recovery port provided in substantially the center of the drain recovery pan 4 has a drain pipe 20.
Linked to Further, below the drain recovery pan 4, a recovery pan temperature adjusting bath 7 is installed as a temperature adjusting means. On the other hand, above the work holder 2, a cooling pipe 8 and a lid 11 for condensing the cleaning vapor are provided.

At the peripheral portion of the bottom of the steam cleaning device, there is provided the above-mentioned rectangular vapor generation tank E so as to surround the drain recovery pan 4, and the vapor generation tank E contains a container 6 for containing a cleaning liquid serving as a steam generation source and the same. The heating source steam generator 5 is composed of a cleaning solution heating bath for heating the.

In the container 6 for storing the cleaning liquid, any one cleaning liquid of CFC 113, methylene chloride, 1,1,1-trichloroethane, isopropyl alcohol, and chloroform is stored. In order to heat the container 6 containing the cleaning liquid, a steam generator 5 such as a cleaning liquid heating bath is arranged like a jacket via a partition wall 5a having good thermal conductivity. Liquids such as water and silicone oil are stored in the heating bath, which are heated by various known methods and set to a predetermined temperature.

Instead of using a heating bath as the above-mentioned generator 5, other heating means such as a hot plate may be used.

It is preferable that the container 6 for containing the cleaning liquid of the present invention is continuously provided so as to go around the peripheral portion of the steam cleaning device as shown in FIG. You may arrange. In any case, it is important that the container 6 and the steam generator 5 be provided so as to surround the drain recovery pan 4.

By the way, in the present invention, a rectangular vapor generation tank E is used.
In order to adjust the surface temperature of the drain recovery pan 4 provided in the center of the drain recovery pan 4 to a temperature lower than the boiling point of the recovery liquid of the drain recovery pan (usually a cleaning liquid and a mixture of the cleaning liquid and the water-based azeotrope), for example, The recovery pan temperature adjusting bath 7 is provided so as to surround the recovery pan 4 with an air layer to some extent.

In the bath 7, a liquid similar to the liquid stored in the cleaning liquid heating bath as the steam generator 5 is stored as a heating / cooling medium.

With this temperature control bath 7, the surface temperature of the drain recovery pan 4 is 5 than the boiling point of the volatile liquid used for drying.
It is set lower by about 10 ℃.

If this surface temperature is set too low, the vapor generation tank E
A part of the steam that flows in from the condenser condenses in the vicinity of the recovery pan 4, making it difficult for the steam to flow toward the cleaning target 1. On the other hand, if this temperature is set too high, the condensate recovered in the recovery pan 4 will be recovered. Evaporation occurs, which causes the inconvenience that impurities such as contaminated water and dirt contained in the drain diffuse and float.

Next, the operation of this embodiment will be described below with the cleaning solution used as IPA. In the case of performing steam cleaning, when the heating source steam generator 5 heats the IPA in the container 6 containing the cleaning liquid, the IPA evaporates, and the evaporated steam 9 evaporates.
And flows into the space F containing the object to be steam-cleaned.
The inflowing steam 9 is the cleaning target 1 held in the space F.
The object 1 to be cleaned is cleaned by evaporating the water or the liquid content attached to the. The drain dropped from the cleaning target 1 is received by the drain recovery pan 4 and discharged through the drain pipe 20. As described above, the drain recovery pan 4 is controlled to have a predetermined temperature by the recovery pan temperature adjusting bath 7, so that the cleaning target 1 is contaminated due to the re-evaporation of the condensate and the vapor 9 Cannot be a factor of disturbance that disturbs the flow toward the cleaning target.

By the way, the vapor 9 that has risen above the space F containing the object to be vaporized condenses when cooled by the cooling pipe 8, becomes dew-like drops, is collected in the collection groove 10, and is discarded or purified. Be reused.

When reusing steam, it is preferable to use a circulation system as shown in FIG.

In FIG. 3, the condensate recovered in the recovery groove 10 passes through the return pipe 32 and is recovered in the recovery tank 37.
Further, unused cleaning liquid is supplied to the recovery tank 37 through the pipe 38. The collected condensate is transported to the overflow type tank 36 by the circulation pump 34, and the filter 33 is provided in the transport pipe.

Impurities in the condensate are removed by this filter 33. The overflow-type tank 36 communicates with the container 6 containing the cleaning liquid, and the liquid level of the cleaning liquid in the container 6 is determined by setting the liquid level of the tank 36.

The circulation pump 34 is started or stopped by detecting the upper surface or the lower surface of the level meter 35. With such a circulation system, the removal of fine particles, which are impurities contained in the condensate, can be carried out extremely effectively and rapidly.

That is, a large amount of impurity fine particles contained in the condensate of IPA is generated in the early stage of drying, and the condensate is removed by passing it through a (non-conductive) filter made of an organic material such as Teflon. The effect of is greatly added,
Fine particles, which are impurities, can be removed extremely effectively.

Below, a specific steam cleaning test was conducted in order to confirm the effect of the steam cleaning apparatus of the present invention. The first steam cleaning device
The structure shown in the figure was used.

The following silicon wafer was used as the steam cleaning target 1.

That is, as the silicon wafer used in this experiment, a silicon wafer that was mirror-finished by an ordinary method and pre-washed through the following washing step was used.

Trichlorethylene 10 min 80 ° C. ultrasound surfactant 5% aqueous 10 min 80 ° C. ultrasonic ethyl alcohol 10 minutes ultrasonic pure rinse (18 M [Omega · cm or _{more) NH 4 OH-H 2 O} 2 -H 2 O (1: 1 : 5) 10 minutes 80 ℃ Ultrasonic deionized water rinse (18MΩ · cm or more) HF immersion (1%) Pure water rinse (18MΩ · cm or more) HC1−H ₂ O ₂ −H ₂ O 10 minutes 80 ° C deionized water rinse (18 MΩ · cm or more) In the steam cleaning of the present invention, isopropyl alcohol was used as a cleaning liquid serving as a steam source, and the temperature of the drain recovery pan was adjusted to 78 ° C.

In the comparative example described below, the temperature of the drain recovery pan was not adjusted.

After performing the steam cleaning of the present invention, the wafer was taken out and the following evaluation was performed. As a comparative drying test, the same drying test was performed using the vapor dryer shown in FIG.
The wafer obtained in this way was also evaluated in the same manner.

(1) Surface dirt As a method for analyzing surface dirt, Auger, ES
Although CA, XMA, IMA, etc. are effective, they are not always effective as an analysis of silicon wafers. In the examples of the present invention, the cleaning degree was determined by detecting spots on the mirror surface of the silicon wafer by a classical optical method. The measurement method is extremely simple.The light source of the microscope is incident on the wafer surface at an angle of about 45 °, and the irradiation surface is viewed with the naked eye from a direction substantially perpendicular to the wafer surface. In the case of a uniform surface to be exhibited, it is considered to have a sufficient degree of cleaning as a substrate surface for a semiconductor integrated circuit device. In the conventional method, a dull cloud, which is often speckled or a brush stroke, is sometimes observed on the whole or a part of the wafer, but in such a case, it is not a clean surface.

Next, the experimental results of the method of the present invention and the comparative example will be shown. 10 silicon wafers each were steam cleaned.

In the present invention, no fog was observed at all, but in the comparative example, fog was observed in 7 out of 10 sheets. Among the comparative examples, there were 3 sheets with no haze, but the entire mirror surface was slightly glossy, and it was observed that the entire surface was hazy. Probably the cleaning was inadequate.

〔The invention's effect〕

The effect of the present invention is clear from the above results. That is, the present invention provides a drain cleaning pan for recovering a liquefied cleaning liquid having an open upper part in a cleaning space in a steam cleaning device in which vapor of a volatile cleaning liquid is brought into contact with a cleaning target housed in the steam cleaning device for steam cleaning. Provided inside, surrounding the drain recovery pan by a container for the cleaning liquid and a steam generator,
Furthermore, the surface temperature of the drain recovery pan is set to 5 from the boiling point of the cleaning liquid.
The temperature adjusting means is maintained at a temperature lower than -10 ° C and lower than the azeotropic point of the cleaning liquid and water, and a discharge pipe for discharging the drain in the drain recovery pan to the outside.

Therefore, according to the steam cleaning apparatus of the present invention, the vapor of the cleaning liquid hardly condenses in the vicinity of the drain recovery pan and smoothly flows toward the cleaning target to efficiently clean the entire surface of the cleaning target. In addition, since the drain recovery pan is provided in the lower part of the cleaning space for accommodating the object to be cleaned, the steam flowing toward the object to be cleaned causes the surface temperature of the drain recovery pan to increase. It is not heated to a temperature at which the drain of the product evaporates. In addition, drain generated on the surface of the object to be cleaned and collected in the drain recovery pan (mixture of cleaning liquid and cleaning liquid / water azeotrope)
Since the re-evaporation is surely prevented by the temperature control by the temperature control means, impurities such as contaminated water and dirt contained in the drain are suspended and scattered, and the cleaning object located above is soiled again. Alternatively, there is no problem that the steam cleaning effect is deteriorated by the steam containing a large amount of water generated from the drain. Therefore, the steam cleaning effect is remarkably improved as compared with the conventional one.

In addition, the steam cleaning device of the present invention has a simple structure, can be economically provided, is easy to operate and maintain, and has the effect of significantly reducing the cleaning cost.

[Brief description of the drawings]

1 is a sectional view showing an embodiment of a steam cleaning apparatus according to the present invention, FIG. 2 is a sectional view taken along the line AA ′ in FIG. 1, and FIG.
FIG. 4 is a drawing showing a circulation system associated with the steam cleaning apparatus of the present invention, and FIG. 4 is a sectional view of a conventional steam cleaning apparatus. 1 ... Object to be cleaned, 2 ... Work holder, 4 ... Drain recovery pan, 6 ... Container for storing cleaning liquid, 7 ... Recovery pan temperature adjusting bath, 33 ... Filter, 37 ... Recovery tank, E ...
... Vapor generating tank, F ... Space containing steam cleaning target.

Claims (2)

(57) [Claims] 1. A cleaning space for accommodating an object to be cleaned, a container under the cleaning space for accommodating the cleaning liquid, and a steam generator for heating and evaporating and evaporating the cleaning liquid in the container. A liquefaction with an open upper part in a steam cleaning apparatus configured to remove water adhering to the surface of the object to be cleaned and / or organic contaminants by bringing the steam generated from the cleaning liquid into contact with the surface of the object to be cleaned. A drain recovery pan for cleaning liquid recovery is provided in the cleaning space, and the drain recovery pan is surrounded by the cleaning liquid storage container and the steam generator. Further, the surface temperature of the drain recovery pan is set to be 5 to the boiling point of the cleaning liquid. A temperature control means for maintaining the temperature at a temperature lower than -10 ° C and lower than the azeotropic point of the cleaning liquid and water, and a discharge pipe for discharging the drain in the drain recovery pan to the outside. Steam cleaning apparatus. 2. The cleaning liquid is Freon 113, methylene chloride,
1,1,1-trichloroethane, isopropyl alcohol,
The vapor cleaning apparatus according to claim 1, wherein the vapor cleaning apparatus is any one of chloroform.