JPS62216602A - Method for recovering organic solvent - Google Patents

Abstract

PURPOSE:To efficiently and safely recover combustible and flammable exhaust gas by cooling and condensing the exhaust gas, and recovering the liquefied org. solvent when the exhaust gas of the vaporized spent org. solvent is recovered. CONSTITUTION:The org. solvent such as an org. solvent for developing a photoresist in a cup 11 which has been vaporized is introduced into a cooling vessel 22 through a suction pipe 21 by evacuating an exhaust pipe 26, and cooled and liquefied therein by a cooler 23. The liquefied org. solvent is introduced into a waste liq. tank 18 through the second liq. discharge pipe 27. About 90% of the vaporized solvent is liquefied by the cooling, and the remaining vaporized solvent is sent to a processing device through an exhaust pipe and a duct. The unvaporized waste liq. in the cup 11 is sent to the waste liq. tank 18 through a waste liq. discharge pipe 17, and stored. This method is also used to recover a solvent from the washing stage of a wafer in a semiconductor producing process.

Description

[Detailed Description of the Invention] [Summary] This is a method for efficiently and safely recovering organic solvents used for developing, cleaning, etc. of photoresist using a small device.

[Industrial application field]

This address is related to the method of recovering IJ31 solvent.
More specifically, the present invention relates to a method for efficiently and safely recovering vaporized organic solvents used in wafer cleaning, photoresist development, etc. in semiconductor device manufacturing processes.

[Conventional technology]

Conventional development of photoresist coated and exposed onto a wafer is described with reference to the cross-sectional view of FIG.
A stage 13 rotated by a motor 12 is placed inside the wafer 1, and a wafer 14 whose surface is coated with photoresist is placed on the stage 13. A developing solution 16 is emitted toward the wafer surface to develop the photoresist coated on the wafer surface. The amount of developing solution used per wafer is from several tens of cc to about 100 cc. The drained liquid passes through the drained liquid discharge pipe 17 and is stored in the drained liquid tank 18, and the drained liquid tank is exhausted through the exhaust pipe 19, and the vaporized organic solvent is stored in the drained liquid tank 18 through the exhaust pipe 19 and a duct (not shown). The vaporized organic solvent is sent to a processing device (not shown), where the vaporized organic solvent is finally processed. The effluent is collected from the effluent tank 18 and disposed of, with a recovery rate of at most 50% if the device shown is used constantly and 20% if the device is used at intervals.
~30%, and the waste liquid itself accumulated in the waste liquid tank 18 is also vaporized.

[Problems that the invention attempts to resolve]

As mentioned above, more than 50% of the waste liquid is vaporized and exhausted, but this exhaust is harmful to the human body in most cases, is flammable and easily ignited, and is If a large amount accumulates, it can explode, so large processing equipment is required to process it, and it takes time. If there is a part of the duct that guides the exhaust that is cooled, the problem is that it liquefies there, leaks from the duct, and ignites, causing a fire.

The present invention was created in light of these points, and an object of the present invention is to provide a method for efficiently and safely recovering 1a solvent using a small device.

c Means for Solving Problem] FIG. 1 is a sectional view of an embodiment of the present invention, and in the same figure, 21
22 is an intake pipe, 22 is a cooler container, 23 is a cooler, 24 is a refrigerant introduction pipe, 25 is a refrigerant discharge pipe, 26 is a second drain discharge pipe, 27 is an exhaust pipe, and 28 is a heat radiation means.

In FIG. 1, the vaporized portion of the organic solvent in the cup 11 is exhausted from the exhaust pipe 26 and introduced into the cooling container 22 through the intake pipe 21, and the cooler 2 in which the refrigerant circulates.
3, the liquefied organic solvent is led into the drain tank 18 through the second drain discharge pipe 28, and the remaining vaporized organic solvent is sent to a processing device (not shown).

[Effect]

In the above method, the vaporized organic solvent in the cup 11 is introduced into the cooling container, where it is cooled and liquefied.The liquefied organic solvent is introduced into the drain tank, and only the remaining vaporized content is removed. Processing is carried out as usual, but as approximately 90% of the vaporized content is liquefied by the cooler and cooling container, the amount of vaporized content sent to the processing equipment via the exhaust pipe and duct is greatly reduced, making organic solvents more efficient. , and be safely recovered.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

In the present invention, as shown in FIG.
A slightly larger cooling container 22 is placed immediately next to the cup 11, and the cooling container 22 and the cup 11 are connected by an intake pipe 21, while the cooling container 22 is exhausted by an exhaust pipe 26.
It is connected to the drain tank 18 by a second drain drain pipe 27 . In the embodiment shown in FIG. 1, the refrigerant is supplied to the cooling container 22 and the cooler 23 from the refrigerant supply pipe 24, and is discharged from the refrigerant discharge pipe 25, but the refrigerant is moved in a circulating manner. For example, O as a refrigerant
Using water at a temperature of 10°C to 10°C, the surfaces of the cooler 23 and the cooling container are kept at 0°C to 10°C, but 0°C is preferable, and the surfaces of the cooler and cooling container are kept at temperatures lower than 0°C ( This is because the moisture in the air that has entered the cooling container 22 becomes ice and adheres to the surface, creating the problem of removing it.Water in the above temperature range is used for air conditioning and cooling in the factory. It is convenient to use water because it is generally used in water. However, it is acceptable to use a refrigerant from outside the waterside.

The material of the cooling container 22 and/or the cooling container 23 has a thermal conductivity of 200 W −m ”'
-K-' or more substances, for example! 11 (Cu) to enhance the cooling effect of the refrigerant.

Cooling 9J> In order to increase the surface area of the cooler 23 in order to increase the cooling effect, the heat dissipation means 28 is shaped like an umbrella shape and a cylinder as shown in FIG. 2(a), a shelf shape as shown in FIG. Attach.

The thickness of the exhaust pipe 26 is such that its cross-sectional area is 3 times that of the drain pipe 17.
Set it to more than double.

In one embodiment of the present invention, the product name 0? To develop the IR photoresist, use the solvent normal heptane at 50 cc per wafer (one wafer is developed every two minutes) at 1°C.
water was used as the refrigerant, the cooler 23 was made of Cu, and 51 to several tens of liters were exhausted per minute from the exhaust pipe 26.
The above solvent was recovered in liquid form. Therefore, less than 10% of the vaporized solvent was directed to the processing equipment, and the processing time was significantly shortened.

The device shown in FIG. 1 is a conventional cup in which a cooling container 22 is connected via an intake pipe 21, but a liquid discharge pipe 17 is connected to a cooling container 22.
may be omitted, and a device may also be used in which the waste liquid is also introduced from the intake pipe 21. In that case, the waste liquid is prevented from coming into direct contact with the cooler 23, so that the cooling efficiency of the cooler 23 is not reduced.

Further, since there is no electrical system in the cooling container shown in FIG. 3, there is an advantage that cooling can be performed safely without spark discharge or the like occurring.

Although the present invention has been described above in detail using photoresist development as an example, the scope of the present invention is not limited to that case, but also extends to cases where organic solvents are used in cleaning and other steps.

〔Effect of the invention〕

As described above, according to the present invention, organic solvents used in cleaning, developing, etc. in the semiconductor device manufacturing process can be efficiently and safely recovered using a small device.

It is effective in improving human safety and work efficiency. Note that the materials of the cooling container and the cooler, and the type of refrigerant are not limited to those described above.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a perspective view of a heat dissipation means for a cooler, and FIG. 3 is a sectional view of a conventional example. In Figures 1 to 3, 11 is a force, 12 is a motor, 13 is a stage, 14 is a wafer, 15 is a developer supply pipe, 16 is a developer, 17 is a drain pipe, and 1 is a drain pipe. liquid tank, 19 is an exhaust pipe, 21 is an intake pipe, 22 is a cooling container, 23 is a cooler, 24 is a refrigerant supply pipe, 25 is a refrigerant discharge pipe, 26 is an exhaust pipe, 27 is a second drain discharge pipe, 28 is a heat radiation means. Agent: Patent Attorney: Moto Kuki; Agent: Yoshio Osuga, Patent Attorney: Invention of Inventive Pig Shoulder - 1 Section 711 Figure 1

Claims (5)

[Claims] (1) In a method of recovering used organic solvents in the form of fine particles, vaporized organic solvents are introduced into a cooling container (22) and cooled by a cooler (23) cooled by circulating refrigerant to liquefy them. Then, the liquefied organic solvent is sent to the drain tank (18) through the second drain pipe (27), and the remaining vaporized organic solvent is sent to the exhaust pipe (26).
A method for recovering an organic solvent, characterized by discharging it at a. 2. A method according to claim 1, characterized in that the cooling container (22) is cooled by passing a refrigerant through it. (3) The method according to claim 1, characterized in that the surface temperature of the cooler (23) is cooled within the range of 0°C to 10°C. (4) The method according to claim 1, characterized in that a cooling container or cooler made of a substance having a thermal conductivity of 200 W·m^-^1·k^-^1 or more is used. (5) The method according to claim 1, characterized in that a liquid having a temperature in the range of -5°C to 10°C is used as the refrigerant.