JPH02185031A - Steam drying equipment - Google Patents

Abstract

PURPOSE:To reduce the generation of defectives such as stains on the surface of a sample by spraying the preheated sample against heated dry steam carried by a carrier gas during a time when the sample is moved in a steam spraying section, heating the sample, vaporizing moisture and drying the sample in a drying chamber. CONSTITUTION:A sample 1 such as a wafer, a disc substrate, etc., is warmed by a sample preheating section 2 composed of a warm bath, moved to a steam spraying section 41, and sprayed against heated dry steam 19 carried by a carrier gas in the section 4. Steam sprayed against the sample vaporizes the moisture of a sample surface by continuously applying heat to water droplets adhering on the sample and a surface thereof and reacts with oxygen. A heating means in the steam spraying section 4 heats the sample so that sprayed steam is not agglomerated. The sample is moved by a carrying moving mechanism 8, but steam is sprayed extending over the whole surface of the sample and the sample is dried. A filter 21 installed between a steam generator 13 and a steam heater 22 removes fine particles in steam and a mist, etc. Accordingly, a steam drier is operated safely at high speed, and stains are difficult to be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a steam drying apparatus, particularly for semiconductor wafers,
The present invention relates to a steam drying device suitable for drying magnetic disk substrates, glass plates, etc. after cleaning.

(Prior art) Regarding conventional steam drying devices of this type, for example, as described in JP-A No. 60-231329, water vapor generated by mixing and burning hydrogen and oxygen is used to place a sample. JP-A-57-42 discloses a device for drying by supplying water into a drying container, and a device for drying using dry nitrogen gas as a related device, but not using water vapor.
As described in No. 121, the water-washed sample is placed in a heated chamber together with the basket, and first, water vapor from pure water generated by ultrasonic vibration is fed into this chamber, and water vapor washing is carried out for a while. There are known devices that dry the product by switching the atmosphere to a drying gas such as nitrogen gas.

[Problem to be solved by the invention]

However, in the former method of generating water vapor by burning hydrogen gas introduced in the above-mentioned conventional technology, residual oxygen gas reacts with water vapor on the sample and causes stains on the wafer surface, for example. Because it burns hydrogen gas to generate water vapor, it is complicated to handle, and there are safety issues. Furthermore, the latter method of drying with nitrogen gas has a problem in that the drying speed is slow because the heat capacity of nitrogen gas is several minutes smaller than that of water vapor.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide an improved steam drying device that is safe, high-speed, less likely to cause stains, and low in cost.

[Means for Solving the Problem] The above object is to provide a water vapor generator, a carrier gas supply section connected to the water vapor generator, and a water vapor that is transported by the carrier gas and fed through a filter. a heated and dried steam supply section comprising a heater;
A sample comprising a sample preheating section, a steam spraying section provided with a heating means, and a drying chamber provided with a heating means successively adjacent to each other, and further including a transport movement Ia side for sequentially moving the sample. a drying section; and a means for connecting and supplying heated and dried steam from the steam supply section to the steam spraying section; thereby, the preheated sample is
This is achieved by a steam drying device having a structure in which the heated drying steam carried by the carrier gas is sprayed while moving through the steam spraying section, is heated, evaporates moisture, and is further dried in a drying chamber. Ru.

f action] The steam generator generates the steam used for drying the sample, and it is carried towards the steam heater by an inert gas such as nitrogen supplied from the carrier gas supply section. On the way, a filter removes microparticles from the steam. , the mist is removed, and then heated to 100°C or higher, preferably 150 to 3
After being heated to about 00° C., it is supplied to the steam spraying section of the sample drying section. On the other hand, a sample such as a wafer or a disk substrate is heated in a sample preheating section consisting of, for example, a hot bath, and then moved to a steam spraying section where it is sprayed with heated and drying steam carried by a carrier gas. The water vapor blown onto the sample continuously applies heat to the sample and water droplets adhering to its surface, thereby evaporating moisture on the sample surface and preventing it from reacting with oxygen and causing stains. The heating means in the steam spraying section heats the sprayed steam so that it does not condense. Further, the sample is moved by a transporting mechanism, and the sample is dried by spraying steam over the entire surface of the sample. Furthermore, in order to prevent the steam in the drying chamber from becoming agglomerated mist and adhering to the sample, the steam in the drying chamber is kept at a temperature of 100°C or higher using heating means such as a heater, while preventing the formation of stains due to the adhesion of mist. dried. Note that the filter provided between the steam generator and the steam heater is for removing microparticles, mist, etc. in the steam, and is made of, for example, a filter filled with glass fiber, synthetic fiber, or the like.

【Example〕

An embodiment of the steam drying apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of the main parts of the steam drying apparatus of the present invention.

The basic structure of a steam drying device is a hot bath 2 that preheats a sample 1 with a large heat capacity (for example, a wafer or a disk substrate) before drying, and a clean heat medium of 50 to 90°C, such as pure water, is supplied to the hot bath 2. A drying chamber 6, which has a liquid supply section 3 for drying the preheated sample 1, a steam nozzle 4 for drying the preheated sample 1, and a heater 5 for preventing generation of mist due to agglomeration of steam. It consists of a steam supply section 7 for supplying clean steam of 150 to 300'C to the steam nozzle 4, and a transport mechanism section 8 for transporting the sample 1 up and down using a pulse motor. The hot tub 2 is filled with a liquid that is a heat medium, such as pure water, and in order to prevent contamination due to liquid pooling, the hot tub has an overflow structure and a liquid supply section that can supply pure water from the bottom. It is connected to 3. The drying chamber 6 has a sealed structure to prevent outside air from entering, and a shutter 10 is installed to prevent steam from leaking outside. An exhaust port 11 is provided to exhaust water vapor from the steam nozzle 4. The sample 1 is attached to an arm 12 connected to the transport mechanism 8 and immersed in the liquid 9 in the hot bath 2 . After the sample 1 is immersed for a certain period of time and the temperature of the sample 1 rises to a predetermined temperature, the sample 1 is slowly transported upward by the arm 12, and water vapor is sprayed onto the surface of the sample 1 from the steam nozzle 4. the result,
Water and the liquid 9 which is a heat medium adhering to the surface of the sample 1 are replaced with water vapor and removed, and the sample 1 is transported to the upper part of the drying device and the drying process is completed.

Figure 2 shows the sample 1 in the steam drying apparatus of Figure 1.
This figure shows the internal structure of the steam supply section 7 used for drying the water vapor.A steam generator 13 in the steam supply section 7 is filled with a liquid free of impurity ions, e.g., pure water, through a filter 14 for removing foreign matter. Water is supplied from the outside, and a portion of it is discharged in a fixed amount from a drain 16 through a metering valve 17 to prevent contamination of the liquid. The steam generator 13 is provided with a heater 18, and steam 19 is generated at a constant rate. This water vapor 19 is supplied to a steam heater 22 through a filter 21 for removing particulates in the milst and water vapor using an inert carrier gas such as nitrogen gas supplied through a filter 20 for removing foreign substances. The temperature is 100°C or higher, preferably 150°C or higher with a heater 23.
A steam transport pipe 2 that is heated to 300°C and has a heat-retaining heater 24 to prevent steam from condensing up to the steam nozzle 4.
5 to transport the steam to the steam nozzle.

FIG. 3 shows the internal configuration of the liquid supply section 3 used to preheat a sample with a large heat capacity in the apparatus shown in FIG.
The liquid supply section 3 consists of a heat exchanger 26 and a liquid heating tank 27, and the liquid supply system is of a flow type to prevent contamination due to liquid accumulation, such as generation of bacteria. filter 28
The pure water that has passed through is heated by the heat exchanger 26 with hot water that is waste liquid from the hot bath 2, then heated to 50 to 90°C by the heater 29 of the liquid heating tank 27, and then supplied to the drying device. Bubbles 30 are generated in the liquid heating tank 27 and become splashes in the hot tub 2, causing stains, so a deaerator 31 is inserted before supplying the hot water to the hot tub 2 to supply hot water without bubbles.

The upper part of the deaerator 31 is open to the atmosphere, and the hot water flows into the hot tub 2.
The water level of the deaerator 31 is set higher than the water level of the hot tub 2 to such an extent that the liquid flows into the hot tub 2.

In the above embodiment, the liquid serving as the heat medium in the hot tub 2 constituting the sample preheating section can be water, alcohol, halogenated organic solvent, etc., and preferably a liquid whose viscosity decreases when heated. It is preferable to use water, especially considering costs, safety, and environmental hygiene.Also, water vapor is preferable as the vapor for drying sample 1, but in some cases, the use of vapor from alcohols, halogenated organic solvents, etc. It is also possible to use an inert gas such as heated nitrogen gas instead of steam. However, as mentioned above, cost and safety.

In consideration of environmental hygiene and the like, a mixed gas of water vapor and nitrogen gas as a carrier gas is preferable. Further, it is preferable that the liquid and vapor used as the heat medium have the same components. It is not preferable to use air as a carrier gas because oxygen in the air, water, and the sample react with each other to generate stains.

In the apparatus configured as shown in Fig. 1, water is used as a heat medium and steam, carrier gas is nitrogen gas, and the temperature of the hot tub is 85°C.
When the temperature of the drying chamber is 250°C, and if we take a magnetic disk substrate with a diameter of about 13 cII+ as an example, even centrifugal drying with a short drying time would require more than 30 seconds, but with the device of the present invention, drying takes less than 15 seconds. It was possible to dry the product with no stains at all. Furthermore, since water vapor is used, the cost is less than 1/10 compared to heating the same volume of nitrogen gas to 200 to 300°C. Furthermore, since flammable vapor such as alcohol is not used, safe drying can be performed.

〔Effect of the invention〕

According to the present invention, a clean drying process can be performed safely and twice as fast as conventional steam drying, thereby reducing the occurrence of defects such as stains on the sample surface caused by contamination.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram of the main parts of the overall configuration of the apparatus which is an embodiment of the present invention, FIG. 2 is a configuration diagram of the steam supply section, and FIG. 3 is the configuration of the liquid supply section that constitutes the hot bath of the sample preheating section. It is a diagram. 1... Sample (disk substrate), 2... Hot tub, 3...
...Hot water supply section, 4...Steam nozzle, 5...Heater, 6...Drying chamber, 7...Steam supply section, 8...Transportation mechanism section, 9...Liquid (pure water ), 10...shutter,
11...Exhaust port, 12...Arm, 13...Steam generator, 14...Filter, 15...Liquid (pure water), 16...Drain, 17...Constant flow valve , 18
...heater, 19...steam (steam), 20.
21... Filter, 22... Steam heater, 23.
... Heater, 24 ... Heat retention heater, 25 ... Steam transport pipe, 26 ... Heat exchanger, 27 ... Liquid heating tank,
28... Filter, 29... Heater, -30...
Bubbles. 31... Defoamer

Claims (1)

[Scope of Claims] 1. A steam generator comprising a steam generator, a carrier gas supply unit connected to the steam generator, and a steam heater to which the steam carried by the carrier gas is fed through a filter. A sample preheating section, a steam blowing section provided with a heating means, and a drying chamber provided with a heating means are successively provided adjacent to each other, and the sample is sequentially moved. a sample drying section comprising a conveying and moving mechanism for causing the sample to dry; and means for connecting and supplying the heated and dried steam from the steam supply section to the steam spraying section; thereby, the preheated sample is A steam drying apparatus having a structure in which the heated and drying steam carried by the carrier gas is sprayed while moving through the steam spraying section, and the moisture is evaporated by being heated, and the moisture is further dried in a drying chamber. 2. The steam drying apparatus according to claim 1, wherein the sample preheating section of the sample drying section comprises a warm bath in which warm water circulates, and the sample is preheated by immersing it in the hot bath.