JPS63160232A - Processing method and apparatus - Google Patents

Abstract

PURPOSE:To improve the yield of a product by using superheated vapor as heated vapor when the heated vapor is condensed on the surface of a material to be treated and treated to vaporize the moisture on the surface of the material, thereby removing the adherence of contaminants. CONSTITUTION:Heaters 5, 8 are set to predetermined conditions, the vapor generation amount of isopropyl alcohol IPA of a vapor generator 2 and the predetermined temperature of a condensing member 4 and a reheater 6 are set. and superheated vapor is condensed and circulated by a cooling tube 3. When a wafer 12 is set in a processing space, the superheated vapor is condensed on the surface of the wafer 12, and flows down to a tray 7 together with a foreign matter, such as adhered water. When it is maintained for a predetermined time, the drying of the wafer 12 is completed. Thus, the superheated vapor is used and reheated to maintain temperature higher than a boiling point, thereby preventing the moisture and contaminants from adhering thereto. Thus, the yield of a product can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a treatment technique in which heated steam is condensed on the surface of an object to be treated.

[Conventional technology]

One of the treatments performed by condensing heated steam on the surface of an object to be treated is so-called steam drying. This is explained in Japanese Patent Application No. 57-89664.

The apparatus used for the above-mentioned steam drying has a steam generating section that stores a processing liquid for forming steam, and the heated steam generated by heating the steam generating section is set at a predetermined position. The drying process is accomplished by moving the heated steam to the object being treated and condensing the heated steam on the surface of the object.

By the way, generally in steam drying, heated steam is generated by heating the processing liquid in the steam generating section to its boiling temperature. Therefore, the heated steam is in a state of saturated steam or nearly saturated steam with a steam pressure of approximately 1 atm.

Now, since the processing liquid is mixed with water vapor in the atmosphere or water evaporated or dripped from the object to be processed, the heated steam that heats and evaporates the processing liquid contains water vapor.

[Problem that the invention seeks to solve]

However, if moisture is present in the steam as described above, the treatment liquid (condensed liquid) is immersed in saturated steam, the moisture on the surface of the workpiece is replaced with a treatment liquid with a low moisture concentration, and the treatment liquid (condensed liquid) is removed in the atmosphere. Steam drying, which evaporates and dries the material, has the problem of locally abnormal oxidation (watermarks) occurring on the surface of the processed material due to the moisture contained in the condensate and the oxygen in the atmosphere. was discovered by the present inventor.

Furthermore, when saturated steam is produced by boiling, mist is often generated in the steam due to the bursting of bubbles at the gas-liquid interface, and this mist is transferred to the object to be processed, causing foreign matter to adhere to the surface of the object. The inventors have discovered that there is a problem that occurs.

An object of the present invention is to provide a technique that can prevent local abnormal oxidation and foreign matter adhesion from occurring on the surface of a workpiece when treating the workpiece by condensing heated steam on the workpiece. be.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means for Solving the Problems] A brief overview of typical inventions disclosed in this application is as follows.

That is, when processing is performed by condensing heated steam on the surface of the object to be treated, superheated steam is used as the heated steam.

[Effect]

According to the above-mentioned means, the temperature of the superheated steam is maintained above the freezing point even if there is a slight change in temperature, etc., so that the water on the surface of the object to be treated is exchanged with the treatment liquid, and then the water in the steam is It will dry out.

Here, the oxygen concentration in the steam is the oxygen concentration in the atmosphere (approximately 20
%), and even if the condensate contains some moisture, no abnormal oxidation will occur on the surface of the object to be treated, thus achieving the above objective.

Furthermore, since the mist is decomposed by reheating the saturated steam, it is possible to prevent contaminants from adhering to the object to be treated, thereby achieving the above object.

[Example 1] FIG. 1(a) is a schematic explanatory diagram showing a steam drying apparatus which is Example 1 of the present invention. 1(b) is a schematic plan view showing a reheating section applied to the above device.

In the steam drying apparatus (processing apparatus) of Example 1, the main body 1 is formed of a cylindrical container.

At the bottom of the main body 1, there is a steam generating section 2 in which isopropyl alcohol (hereinafter abbreviated as IPA), which is a processing liquid, is stored. A cooling pipe 3 is installed for condensing and refluxing the heated steam of the IFA. A condensing member (i!! retracting means) is placed above the steam generating portion 2, a reheating portion 6 around which a heater 5 is attached is placed above the condensing member 4, and a reheating portion 6 is provided above the condensing member 4. heating i￥ls
A tray 7 is provided above each of the trays 6. The condensing member 4 is made of a material having good thermal conductivity, such as silicon carbide (SiC), and has a through hole 4 of a predetermined diameter formed in the plate material.
It is formed by forming a. When the device is used, the temperature is maintained at a temperature slightly lower than the boiling point of IPA (82.5°C), for example, about 70°C, and a part of the heated IPA steam rising from the steam generation section 2, especially the mist, is 41, and the condensed IPA is returned to the steam generating section 2 again. Further, the reheating section 6 is formed by forming a through hole 6a in a plate material made of silicon carbide, and FIG. 1(b) shows this in more detail. When the apparatus is in use, the reheating section 6 is heated by the heater 5 attached around it and maintained at a temperature exceeding the boiling point of IPA, for example, 100.degree. C. or higher. The receiver serves to reheat the IPA vapor that has passed through the condensing member 4 and supply it to the processing space located between the tray 7 and the cooling pipe 3. The heated steam of IPA thus supplied exceeds its boiling point, e.g.
It is superheated steam at ℃. Therefore, the heated steam existing in the processing space is in a completely gaseous state and no mist exists.

Further, a heater 8 for heating the IPA 2 of the steam generating section is installed under the main body 1, and a heat insulating member 9 is connected around the heater 8 and the outer peripheral wall surface of the main body 1.

A drain pipe 7a extends to the outside, passing through the side wall of the main body 1 and the heat retaining member 9 attached thereto, and communicating with the receiving tray 7. The above device is provided with a liquid supply port (not shown) for supplying IPA to the steam generation section 2 and a liquid drain port (not shown) for extracting IPA from the steam generation section. It is possible to supply and exchange IPA as appropriate.

Next, the operation of this embodiment will be explained.

First, the heaters 5 and 8, etc. are set to predetermined conditions, and the amount of steam generated by the steam generating section 2, the condensing member 4, the reheating section 6, etc. are set and maintained at predetermined temperatures, and the temperature is set at a predetermined temperature. Superheated steam is supplied to the processing space, and the superheated steam is condensed and refluxed in the cooling pipe 3 to reach a steady state. The vapor level 10 in the steady state is shown by a chain double-dashed line near the top of the device.

Next, the semiconductor wafer 12 stored in the cassette 11 is
is inserted from the top of the apparatus, and the receiver is set at a predetermined position in the processing space located above the plate 7. Then, the superheated steam in the processing space condenses on the surface of the semiconductor wafer 12, and the condensed IPA flows down with foreign substances such as water attached to the surface, and the receiver falls onto the tray 7. go. The above receiver is plate 7
The condensed IPA that has fallen is discarded through the drain pipe 7a. By maintaining this state for a predetermined period of time,
The drying process of the semiconductor wafer 12 described above is accomplished.

As described above, according to this embodiment, the following effects can be obtained.

(1) By providing the reheating section 6 between the steam generation section 2 and the processing space, the heated steam of IPA rising from the steam generation section 2 heated by the heater 8 is heated by the above reheating. Since further heating can be performed in the section 6, superheated steam can be easily supplied to the processing space.

(2) As a result of (1) above, it is possible to create a state in which no mist exists in the processing space, so that pollutants present in the steam generation section, etc. are captured in the mist and transported to the processing space. can be prevented.

(3) According to (2) above, the semiconductor wafer 12 set in the processing space can be dried with highly clean superheated steam, so that foreign matter will not adhere to the surface of the semiconductor wafer 12 after processing. This can be effectively prevented.

(4) A condensing member 4 between the steam generation section 2 and the reheating section 6
By providing this, it is possible to prevent the condensation member 4 from condensing the mist that easily absorbs contaminants generated from the steam generation section 2, which is particularly likely to become a source of contamination, and from rising to the reheating section 6. The cleanliness of the supplied superheated steam can be further improved.

C5) According to (2) and (4) above, it is possible to further reduce the adhesion of foreign substances to the semiconductor wafer 12 after processing.

[Embodiment 2] FIG. 2 is a schematic explanatory diagram showing a steam drying apparatus according to Embodiment 2 of the present invention.

The vapor drying apparatus of the second embodiment has the same basic configuration as the apparatus of the first embodiment. However, the steam generating section 2 is formed at the bottom of a box 13 made of silicon carbide, and the reheating section 6 having a through hole 6a is formed in the clay wall of the box 13. That is, in comparison with the first embodiment, the bottom part of the steam generating part 2 and the reheating part 6 are integrally formed. Therefore, the condensing member 4 is also provided inside the box 13.

As described above, according to this embodiment, the following effects can be obtained.

(1) By integrally forming the bottom part of the steam generation section 2 and the reheating section 6, it is possible to heat the IPA in the steam generation section 2 and to prevent the IPA generated and rising from the steam generation section 2. Reheating of the heated steam can be performed only by the heater 8 installed under the bottom.

(2) According to (1) above, substantially the same effect as in the first embodiment can be obtained with one heat source.

[Embodiment 3] FIG. 3 is a schematic explanatory diagram showing a steam generator according to Embodiment 3 of the present invention.

In the steam drying apparatus of this embodiment, a steam generation tank 14 having a steam generation section in which IPA is stored at the bottom thereof and a processing tank 15 having a processing space are connected by a steam transfer section 16 at the top of each. This is what happens. The steam generation tank 14 and the processing tank 15 are cylindrical containers, and the moving part 1
6 consists of a cylindrical body.

As in the first embodiment, a heater 8 is installed below the steam generating section 2, and a condensing member 4 is attached above the steam generating section 2.

A cooling pipe 3 is attached below the processing space of the processing tank 15. Further, the steam moving section 16 is provided with a reheating section 6 having a through hole 6a around which a heater 5 is attached. A heat insulating member 9 is attached to the outer periphery of the processing tank 14 near the cooling pipe 30 from the steam transfer section 16 .

Next, the operation of this embodiment will be explained.

First, the IPA in the steam generating section 2 is heated with the heater 8, and the IPA is heated.
generates heating steam. The mist contained in this heated steam is removed by the condensing member 4, and the steam generating tank 14
The steam rises inside, is heated to superheated steam in the reheating section 6, and reaches the processing tank 15. The superheated steam that has reached the processing tank 15 in this way condenses on the surface of the semiconductor wafer 120 housed in the cassette 11 that has been set at a predetermined position, and the drying process of the semiconductor wafer 12 is started.

The IPA condensed on the surface of the semiconductor wafer 12 falls to the bottom of the processing tank 15. Moreover, the superheated steam that is not condensed on the way is condensed in the cooling pipe 3 and similarly falls to the bottom of the processing tank 15. The condensed IPA that has fallen to the bottom of the treatment layer 15 is discarded from a drain port (not shown) provided at the bottom.

By continuing the above state for a predetermined period of time, the drying process of the semiconductor wafer 12 is achieved.

As described above, according to this embodiment, the following effects can be obtained.

(1) Regarding a steam drying device in which a steam generation tank 14 and a processing tank 15 are connected by a steam transfer section 16, a reheating section is provided in the steam transfer section 16 located between the steam generation section 2 and the processing space. By installing 6, superheated steam can be supplied to the processing space.

(2) According to the above (1), substantially the same effect as in the case of the first embodiment can be obtained even in a two-tank type apparatus having a structure in which the generation section 2 and the processing space are separated.

Although the invention made by the present inventor has been specifically explained above based on Examples, it goes without saying that the present invention is not limited to the Examples and can be modified in various ways without departing from the gist thereof. Nor.

For example, the structure of the reheating section 6, its forming material, and its installation position are not limited to those shown in the embodiments described above, and it goes without saying that various changes can be made within the range that the intended purpose can be achieved. Further, in the embodiment, only the case in which the condensing member 4 is installed is shown, but the condensing member 4 does not necessarily have to be provided. Furthermore, in the second embodiment, the reheating part 6 and the bottom part are integrated, but they may be separate parts as long as they can transfer heat from the heater 8 to the reheating part 6. good.

In addition, although a specific apparatus was shown in the above embodiment, the steam drying method (processing method) according to the present invention includes not only the apparatus of the above embodiment but also an apparatus equipped with a means for supplying superheated steam to the processing space. Anything can be applied.

Note that in the above embodiments, no particular explanation was given regarding the method of generating heated steam. This is because no special conditions are particularly required when heating the IPA in the steam generating section 2.

However, there are conditions that are particularly effective. I will explain it next.

FIG. 4 is a graph showing the boiling curve of IPA.

Here, the horizontal axis is the temperature difference (1) between the boiling point of IPA and the heat transfer surface.
, the vertical axis is the heat flux (K
cal/m'hr) are shown respectively.

In FIG. 4 above, A-B is a natural convection heat transfer region, B-C is a nucleate boiling region, and D to E are film boiling regions. That is, as the temperature difference between the heat transfer surface (bottom surface of the steam generating section 2) and the boiling point of IPA increases, each of the above regions appears. The natural convection region is a boiling phenomenon in which steam is generated only through convection of IPA, and is a region where bubbles are not generated. The subsequent nucleate boiling region is a region exhibiting a boiling phenomenon accompanied by the generation of bubbles, and the film boiling region is a region exhibiting a boiling phenomenon in which bubbles are generated so intensely that the liquid I'PA does not come into contact with the heat transfer surface. It is.

As in the above embodiment, when the main purpose is to improve the cleanliness of the process, the IPA stored in the steam generating section 2
It is desirable that the boiling of the IPA be as gentle as possible to prevent contaminants from entering the gas phase. Therefore, it is extremely desirable to generate steam in the natural convection heat transfer region A-B, where the movement of the liquid surface of the stored IPA is quiet because no bubbles are generated. In particular, if the apparatus does not have the condensing member 4, it is difficult to remove the mist, which often contains contaminants from the steam generating section 2, so it is particularly effective to carry out the cleaning in the above region.

In the above explanation, the invention made by the present inventor was mainly applied to a steam drying device, which is the background field of application. This technology can be applied to anything that processes steam by condensing it on its surface.

〔Effect of the invention〕

A brief explanation of the effects obtained by typical inventions disclosed in this application is as follows.

That is, when processing is performed by condensing heated steam on the surface of the object to be treated, by using superheated steam as the heating steam, condensation and evaporation of the processing steam can be simultaneously performed on the surface of the object to be treated during steam immersion. Therefore, it is possible to prevent local abnormal oxidation (watermark) that occurs on the surface of the workpiece due to moisture contained in the condensate and oxygen in the atmosphere. Furthermore, superheated steam does not generate mist even if there is a slight change in temperature, so
It is possible to effectively prevent pollutants from being taken into the mist and transported. Therefore, it is possible to prevent foreign matter from adhering to the surface of the processed object due to the above-mentioned contaminants.

Further, by providing a reheating means between the steam generation section and the processing space, the heated steam rising from the steam generation section can be reheated, so the superheated steam can be easily formed. It can be supplied to the processing space.

[Brief explanation of the drawing]

FIG. 1(a) is a schematic explanatory diagram showing a steam drying apparatus according to Embodiment 1 of the present invention, FIG. FIG. 3 is a schematic explanatory diagram showing a steam drying apparatus according to Embodiment 2 of the invention; FIG. 3 is a schematic explanatory diagram illustrating a steam generator according to Embodiment 3 according to the invention; FIG. 4 is a graph showing the 41 curve of IPA. . 1... Main body, 2... Steam generation section, 3... Cooling pipe,
4... So cool! Member (condensation means), 4a... through hole,
5... Heater, 6... Reheating part, 6a... Through hole, 7... Receiver is plate, 7a... Drain pipe, 8... Heater, 9... Heat retention member, DESCRIPTION OF SYMBOLS 10... Steam surface, 11... Cassette, 12... Semiconductor wafer, 13... Box body, 1
4... Steam generation tank, 15... Processing tank, 16... Steam moving section. Agent Patent Attorney Katsuo Ogawa, I Fig. 1 (1) Fig. 2/ 3- “I White; 4;

Claims (1)

[Scope of Claims] 1. A processing method for treating an object by condensing superheated steam on the surface of the object. 2. The processing method according to claim 1, wherein the superheated steam is formed by reheating steam evaporated from a processing liquid reservoir. 3. A processing device that processes the object by condensing heated steam on the surface of the object, in which a reheating means is installed between the steam generation section and the set position of the object. Processing equipment. 4. The processing apparatus according to claim 3, wherein the reheating means is made of a plate material having a through hole formed of a heat transfer material. 5. The processing apparatus according to claim 3, wherein a condensing means is installed between the steam generating section and the reheating means.