JP2557515B2 - Steam dryer - Google Patents

Description

The present invention relates to a steam dryer, and more particularly to a steam dryer suitable for drying semiconductor wafers, magnetic disk substrates, glass substrates and the like after cleaning.

[Conventional technology]

For this type of conventional steam dryer, for example,
As described in JP-A-60-231329, a device for feeding and drying water vapor generated by mixing and burning hydrogen and oxygen into a drying container on which a sample is placed, As described in JP-A-57-42121 as a non-drying but related to drying by using dry nitrogen gas, the washed sample is placed in a heated chamber together with a basket, and first, There is known a device in which water vapor generated from pure water generated by ultrasonic vibration is fed into this chamber, washed with water vapor for a while, and then the atmosphere is changed to a dry gas such as nitrogen gas for drying.

[Problems to be Solved by the Invention]

However, in the former type of device that burns hydrogen gas to generate water vapor, which is introduced in the above conventional technique,
The residual oxygen gas reacts with the water vapor on the sample and causes, for example, a stain on the wafer surface, and since hydrogen gas is burned to generate water vapor, handling becomes complicated and there is a safety management problem. . Further, in the latter method of drying with nitrogen gas, there is a problem that the drying speed is slow because the heat capacity of nitrogen gas is as small as a fraction of that of water vapor.

It is an object of the present invention to solve the above problems, and to provide an improved steam drying apparatus which is safe and high-speed, is less likely to cause spots, and is low in cost.

[Means for solving the problem]

The above-mentioned object includes a steam generator, a carrier gas supply unit connected to the steam generator, and a steam heater for sending steam carried by the carrier gas through a filter. A dried water vapor supply unit; a sample preheating unit, a water vapor spraying unit provided with a heating unit, and a drying chamber provided with a heating unit are sequentially provided adjacent to each other, and a transport moving mechanism for sequentially moving the sample And a means for connecting and supplying heated and dried steam from the steam supply section to the steam spraying section; whereby a preheated sample is sprayed with the steam. Steam drying, which has a structure in which it is sprayed on heated dry steam carried by a carrier gas while it is being moved to heat it to evaporate water and then dried in a drying chamber. The location, is achieved.

[Action]

The water vapor generator generates water vapor used for drying the sample and is carried toward the water vapor heater by an inert gas such as nitrogen supplied from the carrier gas supply unit. Removed and steam steam heater, more than 100 ℃, preferably 150 ~ 300 ℃
After being heated to a certain degree, 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 warmed in a sample preheating section consisting of a hot bath, for example, and then moved to a steam spraying section where it is sprayed on the heated dry steam carried by a carrier gas. The water vapor sprayed on the sample continuously heats the water droplets attached to the sample and its surface to evaporate the water on the sample surface and react with oxygen to prevent generation of stains. The heating means in the steam spraying section heats the sprayed steam so that it does not aggregate. Further, although the sample is moved by the transfer moving mechanism, the sample is dried by spraying the steam all over the sample. Furthermore, in order to prevent the vapor from becoming agglomerated mist in the drying chamber and adhering to the sample, the vapor in the drying chamber is kept at 100 ° C or higher by a heating means such as a heater, while preventing the generation of stains due to the mist attachment. To be dried. The filter provided between the steam generator and the steam heater is for removing fine particles, mist and the like in the steam, and is composed of, for example, glass fibers or synthetic fibers filled therein.

〔Example〕

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

The basic structure of the steam drying device is a warm bath 2 for preheating a sample (for example, a wafer or a disk substrate) 1 having a large heat capacity before the drying process, and a clean heat medium at 50 to 90 ° C., for example, pure water, is supplied to this warm bath 2. A liquid supply unit 3 for drying, a steam nozzle 4 for drying the preheated sample 1, and a drying chamber 6 having a heater 5 for preventing mist generation due to the agglomeration of steam, and the steam nozzle 4 at 150 to 300 ° C. 2 includes a water vapor supply unit 7 for supplying clean water vapor and a transport mechanism unit 8 for vertically transporting the sample 1 using a pulse motor. The hot tub 2 is filled with a liquid which is a heat medium, for example, pure water, and the structure of the hot tub is an overflow type in order to prevent contamination due to the liquid pool, and a liquid supply unit capable of supplying pure water from the lower portion. It is connected to 3. The drying chamber 6 has a closed structure that prevents outside air from entering inside, and a shirt 10 and an exhaust port 11 are provided to prevent steam from leaking outside, and the steam nozzle 4
Exhaust water vapor from. The sample 1 is attached to an arm 12 connected to the transport mechanism 8 and immersed in the liquid 9 in the warm bath 2. After immersing for a certain period of time and the temperature of the sample 1 rises to a predetermined temperature, the sample 1 is slowly transported to the upper part by the arm 12 and the steam is sprayed from the steam nozzle 4 onto the surface of the sample 1. As a result, water attached to the surface of the sample 1 and the liquid 9 which is the heat medium are replaced with steam and removed, and the sample 1 is conveyed to the upper part of the drying device and the drying process is completed.

FIG. 2 shows the internal structure of the steam supply unit 7 used for drying the sample 1 in the steam drying apparatus of FIG. The inside of the steam generator 13 in the steam supply unit 7 is supplied with a liquid without impurity ions, for example, pure water, from the outside through a filter 14 for removing foreign matters, and part of it is for preventing the liquid from being contaminated. A certain amount is discharged from the drain 16 through the metering valve 17. A heater 18 is attached to the steam generator 13.
Is provided, and the steam 19 is generated at a constant speed. The water vapor 19 is a filter for removing fine particles in the mist and water vapor by an inert carrier gas, for example, nitrogen gas, which is supplied through a filter 20 for removing foreign matters.
It is transported to the steam heater 22 through 21 and heated to 100 ° C by the heater 23.
As described above, the steam is transported to the steam nozzle by the steam transport pipe 25 which is heated to preferably 150 to 300 ° C. and has the heat retention heater 24 for preventing the steam from agglomerating up to the steam nozzle 4.

FIG. 3 shows the internal structure of the liquid supply unit 3 used for preheating a sample having a large heat capacity in the apparatus of FIG. The liquid supply unit 3 is composed of a heat exchanger 26 and a liquid heating tank 27, and the liquid supply system is of a flow type so as to prevent contamination by the liquid pool, for example, generation of bacteria and the like. The pure water that has passed through the filter 28 is heated by the waste water from the warm bath 2 by the heat exchanger 26, and then heated by the heater 29 of the liquid heating tank 27.
After heating to ~ 90 ° C, supply to a drying device. Liquid heating tank 27
In this case, bubbles 30 are generated, which causes splashes in the hot tub 2 to cause spots. Therefore, before supplying to the hot tub 2, the deaerator 31 is inserted to supply hot water without bubbles. The upper portion of the defoamer 31 is open to the atmosphere, and the water level of the liquid level of the defoamer 31 is set higher than the water level of the hot tub 2 so that hot water flows into the hot tub 2.

As the liquid serving as the heat medium of the hot tub 2 that constitutes the sample preheating unit in the above-described examples, water, alcohols, halogenated organic solvents, and the like can be used, and a liquid whose viscosity decreases by heating is preferable. . Especially cost, safety,
Considering environmental hygiene, it is desirable to use water. As the vapor for drying the sample 1, steam is preferable,
In other cases, it may be replaced by a vapor of alcohols, halogenated organic solvents, etc., and an inert gas such as heated nitrogen gas may be used instead of the vapor.
However, as described above, in consideration of cost, safety, environmental hygiene, etc., a mixed gas of water vapor and nitrogen gas as a carrier gas is preferable. Further, it is preferable to use the same liquid and vapor components as the heat medium. It is not preferable to use air as the carrier gas because oxygen in the air reacts with water and the sample to generate spots.

In the device having the configuration shown in FIG. 1, water is used as a heat medium and steam, and carrier gas is used as nitrogen gas.
When the temperature in the drying chamber is 250 ° C, the diameter of the sample is approximately 1
Taking a 3 cm magnetic disk substrate as an example, the apparatus of the present invention was able to dry in 15 seconds or less, even though centrifugal drying, which has a short drying time, required 30 seconds or more to dry, and no stain was observed. In addition, since steam is used, the cost is lower than when heating the same volume of nitrogen gas to 200 to 300 ° C.
It became less than 1/10. Furthermore, since flammable vapor such as alcohol is not used, safe drying can be performed.

〔The invention's effect〕

According to the present invention, since a safe and clean drying process can be performed at a speed more than twice as fast as the conventional vapor drying, it is possible to reduce the occurrence of defects such as stains on the sample surface due to adhesion of contaminants.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a main part of the overall configuration of an apparatus according to an embodiment of the present invention, FIG. 2 is a configuration diagram of a steam supply unit, and FIG. 3 is a configuration of a liquid supply unit which constitutes a warm bath of a sample preheating unit. It is a figure. 1 ... Sample (disk substrate), 2 ... Hot tub, 3 ... Hot water supply part, 4 ... Steam nozzle, 5 ... Heater, 6 ... Drying room, 7 ... Steam supply part, 8 ... Transport mechanism part, 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 insulation heater, 25 ... Steam transport pipe, 26 ... Heat exchanger, 27 ... Liquid heating tank, 28 ... Filter, 29
… Heater, 30… Bubbles, 31… Defoamer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 62-173720 (JP, A) JP 63-4616 (JP, A) JP 63-36533 (JP, A) JP 63- 307742 (JP, A)

Claims (2)

(57) [Claims] 1. A steam generator, a carrier gas supply unit connected to the steam generator, and a steam heater for supplying the steam carried by the carrier gas through a filter. A heated and dried steam supply unit;
Sample drying comprising a sample preheating unit, a steam spraying unit provided with a heating unit, and a drying chamber provided with a heating unit, which are sequentially adjacent to each other, and further has a transport moving mechanism for sequentially moving the sample. Part and; means for connecting and supplying heated and dried steam from the steam supply part to the steam spraying part; carrier gas during which the preheated sample moves through the steam spraying part. A steam drying apparatus having a structure in which the steam is heated by being heated by the heated and dried steam conveyed by the above method to evaporate moisture, and 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 is constituted by a warm bath in which warm water is circulated, and the sample is preheated by being immersed in the warm bath.