JP2998181B2 - High boiling point gas recovery method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for recovering a gas that needs to be replaced with an inert gas by maintenance or the like for a toxic, corrosive, or flammable gas. For the method of recovering high-boiling gas with low boiling point, for the purpose of safe, rapid and reliable recovery, semiconductor manufacturing equipment used for film formation or etching, etc. When removing the high-boiling gas in the supply pipe for feeding
The gas cylinder is configured to be cooled and recovered to a temperature lower than the temperature in the supply pipe.

[Industrial applications]

The present invention relates to a method for recovering a gas that requires replacement of a toxic, corrosive or flammable gas with an inert gas for maintenance or the like, and more particularly to a method for recovering a high boiling point gas having a low vapor pressure at room temperature.

In recent years, the technical progress of integrated circuit semiconductor devices has been remarkable, and accordingly, in a wafer process, various high-pressure gases have been used in film forming apparatuses for metal, semiconductor, insulating films and the like or in etching apparatuses.

Among them, many toxic, corrosive or flammable gases are used, so equipment improvement, breakdown, maintenance (maintenance)
For example, it is often necessary to replace the inside of the apparatus or the supply pipe with an inert gas such as nitrogen.

For this reason, it is necessary to develop a safe, quick, and reliable method of recovery.

[Conventional technology]

 FIG. 3 is an explanatory view of a conventional example.

In the figure, 21 is a semiconductor manufacturing apparatus, 22 is a gas cylinder, 23 is a supply pipe, 24 is an exhaust pipe, 25 is a bypass exhaust pipe,
26 is an exhaust gas treatment device, 27 is a scrubber, and 28 is an inert gas.

In the manufacture of semiconductor devices, in the wafer process,
Various toxic, corrosive, or combustible high-pressure gases are used in film-forming apparatuses or etching apparatuses for metal, semiconductor, insulating films, and the like. Later, trichlorosilane (SiHCl ₃ ), tungsten hexafluoride (WF ₆ ), etc. are used in a chemical vapor deposition apparatus for film formation, and silicon tetrachloride (SiCl ₄ ) and boron trichloride are used in an etching apparatus. (BCl ₃ ) and the like are often used.

In order to deal with the harmfulness of these gases, a leak check should be performed periodically, and since high purity is always required as a semiconductor material gas, dry and clean Periodic refresh with an inert gas is required.

For this reason, when performing maintenance, it is necessary to remove toxic, flammable, or corrosive gases from the piping system in advance, and to maintain a safe state for humans and equipment.

In the prior art, an exhaust treatment system as shown in FIG. 3 was used as a method for extracting a high-boiling gas or the like in the process of replacing a high-boiling gas or the like in a pipe with an inert gas. .

The length of the supply pipe 23 for the actual gas is much longer than the length of the exhaust pipe 24 from the semiconductor device 21 to the scrubber 27. Nitrogen is supplied as an inert gas from the inert gas inlet 28 and supplied to the supply pipe. The high-boiling gas was discharged from 23 through the semiconductor device 21, the exhaust pipe 24, the exhaust processing device 26, and the scrubber 27.

However, for high-boiling gas, the vapor pressure is 0 to 1.
5 kg / cm ² or lower, and the actual gas is supplied under the condition of supply pressure = vapor pressure. If there is uneven temperature in the supply path, a gradient will occur in the vapor pressure and low pressure The part becomes saturated and re-liquefies. For this reason, a lot of man-hours and costs were required for the process of extracting the actual gas.

[Problems to be solved by the invention]

Therefore, the following problems occur in the gas replacement method using the conventional exhaust treatment device.

In other words, since a large amount of gas re-liquefaction occurs due to uneven ambient temperature in the supply piping system, man-hours are required for gas replacement work for vaporizing and removing the re-liquefied gas in the gas supply piping. It takes time.

Since the reliquefaction phenomenon occurs in the exhaust processing system, the processing time of the gas replacement is not constant. In addition, a large amount of gas is generated during the repair work in the event of a breakdown, which is dangerous to the human body.

In the case of the exhaust gas treatment system, in the case of the inert gas replacement process, the flow rate of the gas passing through the waste treatment system is several times larger than that of the etching or film formation process, that is, the reaction product of the target gas is increased. Rapidly grows and accumulates in the piping, causing many failures such as clogging of exhaust treatment devices, especially pumps.

In the case of using a dry abatement agent in an exhaust treatment system, the use amount of the dry abatement agent increases, the running cost increases, and the operation rate decreases.

The reliquefied gas will be discarded, and the gas consumption will increase.

The present invention has been made in view of the above circumstances, and has as its object to provide a method for recovering a high-boiling gas safely, quickly, and reliably in a gas recovery operation in a supply pipe of a high-boiling gas to a semiconductor device. Things.

[Means for solving the problem]

FIG. 1 is a diagram illustrating the principle of the present invention and a configuration diagram of an embodiment, and FIG. 2 is a water cooling jacket of the present invention.

In the figure, 1 is a semiconductor manufacturing equipment, 2 is a gas cylinder, 3
Is a supply pipe, 4 is an exhaust pipe, 5 is a bypass exhaust pipe, 6 is an exhaust treatment device, 7 is a scrubber, 8 is an inert gas, 9 is a water cooling jacket, and 10 is a cooling water temperature controller.

As described above, in the conventional technology, the exhaust treatment system is used, and the gas having a low vapor pressure has uneven pressure.
Re-liquefaction takes place and this elimination requires a great deal of labor, time and money.

For this reason, in the present invention, the gas cylinder 2 itself is cooled to a temperature lower than the ambient temperature, the gas vapor pressure inside the gas cylinder 2 is kept low, and a pressure gradient is formed between the gas cylinder 2 and the supply pipe 3. Cause.

Thereby, the gas flows backward from the supply pipe 3 on the high pressure side to the gas cylinder 2 on the low pressure side and is collected, so that the gas in the supply pipe 3 can be discharged.

That is, an object of the present invention is to remove a high-boiling gas from a supply pipe 3 for feeding the high-boiling gas from a gas cylinder 2 of a high-boiling gas to a semiconductor manufacturing apparatus 1 used for film formation or etching. This is achieved by cooling and recovering the gas cylinder 2 to a temperature lower than the temperature in the supply pipe 3.

[Action]

With the above configuration, in the present invention, the vapor pressure in the gas cylinder is always lower than that in the supply pipe regardless of the temperature unevenness in the supply pipe.

As a result, the gas flows back into the gas cylinder on the low pressure side from the supply pipe with a relatively high vapor pressure, and is collected.
As a result, gas can be released from the supply pipe.

〔Example〕

FIG. 1 is a configuration diagram of one embodiment of the present invention, and FIG. 2 is a water cooling jacket used in one embodiment of the present invention.

In the figure, 1 is a semiconductor manufacturing equipment, 2 is a gas cylinder, 3
Is a supply pipe, 4 is an exhaust pipe, 5 is a bypass exhaust pipe, 6 is an exhaust treatment device, 7 is a scrubber, 8 is an inert gas, 9 is a water cooling jacket, 10 is a cooling water temperature controller, 11 is a base, and 12 is A water cooling tube, 13 is a supply port, 14 is a discharge port, 15 is a heat insulating material, and 16 is a clamp belt.

As shown in FIG. 1, a high-boiling gas in a supply pipe 3 for supplying a high-boiling gas from a gas cylinder 2 of a high-boiling gas to a semiconductor manufacturing apparatus 1 used for film formation or etching. In removing the gas, the supplied high-boiling-point gas cylinder 2 is cooled to a temperature lower than the temperature in the supply pipe 3 and recovered.

As a first embodiment of the method for cooling the gas cylinder 2, a water cooling jacket is used as shown in FIG.

As shown in Fig. 2, the water-cooled jacket uses a copper-made base 2 consisting of a 2-fold copper cylinder with a thickness of 2 mm for wrapping the sides of the gas cylinder 2 and a heat-exchange pipe with a diameter of 10 mm on the outside. The copper water cooling tube 12 is welded zigzag.

Then, cold water of about 5 ° C. is introduced from the supply port 13 of the water cooling pipe 12 and discharged from the discharge port 14.

A heat insulating material 15 is wound around the outside of the water cooling tube, and is stopped with a clamp belt 16.

The following table shows an example of the vapor pressure of a high-boiling gas when the gas cylinder is cooled using the apparatus of the present invention.

As can be seen from the above table, if the gas cylinder 2 is cooled to 10 to 20 ° C. with respect to the room temperature, the difference in steam pressure based on the temperature difference between the gas cylinder 2 and the supply pipe 3 causes the supply pipe to be cooled. Most of the high-boiling gas inside is recovered in the gas cylinder.

This method is applied to rough evacuation (primary exhaust) at the time of maintenance, whereby most of the high-boiling gas in the supply pipe 3 is recovered in the gas cylinder 2.

Thereafter, the valve between the semiconductor device and the supply pipe is opened to perform secondary exhaust of minute residual gas.

As a second embodiment for cooling the gas cylinder 2, there is a method of immersing the gas cylinder 2 in a jar filled with ice water or salt water. As a third embodiment, cool air is blown on the gas cylinder 2. A method is also possible.

〔The invention's effect〕

According to the present invention, the following effects can be obtained.

Shortening and stabilizing gas replacement work.

Reduce load and cost of exhaust treatment equipment, and avoid unsafety due to failure of exhaust treatment equipment.

Effective use of gas by reliquefied gas recovery.

Improved safety due to reduced exhaust treatment work.

As described above, the man-hour and cost of the collection work are reduced, which greatly contributes to the improvement of safety.

[Brief description of the drawings]

 FIG. 1 is a block diagram of one embodiment of the present invention, FIG. 2 is a water cooling jacket used in one embodiment of the present invention, and FIG. 3 is an explanatory diagram of a conventional example. In the figure, 1 is a semiconductor manufacturing apparatus, 2 is a gas cylinder, 3 is a supply pipe, 4 is an exhaust pipe, 5 is a bypass exhaust pipe, 6 is an exhaust processing apparatus, 7 is a scrubber, 8 is an inert gas, and 9 is a water cooling jacket. , 10 is a cooling water temperature controller, 11 is a base, 12 is a water cooling tube, 13 is a supply port, 14 is a discharge port, 15 is a heat insulating material, and 16 is a clamp belt.

Claims (1)

(57) [Claims] 1. A method for removing a high-boiling gas in a supply pipe for feeding the high-boiling gas from a gas cylinder of a high-boiling gas having a boiling point near room temperature and having a low vapor pressure at room temperature in a semiconductor manufacturing apparatus. Cooling the inside of the gas cylinder of the high-boiling gas to a temperature lower than the temperature of the supply pipe, thereby recovering the high-boiling gas in the supply pipe to the gas cylinder. Gas recovery method.