JP3027778B2 - Purge gas introduction device for pressure reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-reducing device pressure-increasing purge gas introducing device for introducing a purge gas into a pressure-reducing device in order to raise the pressure in the pressure-reducing device.

[0002]

2. Description of the Related Art For example, an etching step in a semiconductor manufacturing process is performed in a process chamber (decompression device) under a vacuum atmosphere. When loading or unloading a workpiece into or from the process chamber, the atmosphere in the process chamber is set to approximately the atmospheric pressure, or set to approximately the same pressure as the atmosphere in the load lock chamber connected to the process chamber. The inflow of air and the like is prevented. In order to increase the pressure in the chamber, an inert gas such as N ₂ gas is supplied as a purge gas into the chamber.

[0003] As described above, as equipment for introducing a purge gas into a decompression device such as a process chamber, conventionally, a purge gas for increasing the pressure of a decompression device for introducing a purge gas supplied from a purge gas supply source through a supply pipe into the decompression device has been used. The introduction device was attached to various decompression devices.

Here, when the purge gas introduced into the decompression device by the purge gas introduction device contains moisture, there is a problem that the moisture condenses in the decompression device and contaminates the atmosphere in the device. When moisture is mixed in the process chamber, the evacuation time until the pressure in the chamber reaches the set value is lengthened, and the operation efficiency is extremely deteriorated. Therefore, a method of depressurizing and removing moisture in the purge gas has been adopted in the conventional purge gas introducing device for increasing the pressure of the pressure reducing device by the principle of a cold trap.

[0005]

In the above-described conventional purge gas introducing apparatus for increasing the pressure of the pressure reducing apparatus, the purge gas is cooled to a low temperature due to the cold trap, and then the supply pipe disposed at normal temperature (clean room) is connected. As described above.

As a result, moisture in the clean room is condensed on the outer wall of the supply pipe arranged at normal temperature due to a temperature difference between the inside and outside of the pipe. There is a problem that the condensed water droplets and impurities attached to the water droplets form pools in the clean room, and the clean room is locally contaminated, and finally, these scatter and contaminate the clean room.

SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a pressure-reducing device pressure-increasing purge gas introducing device capable of preventing dew condensation on an outer wall of a supply pipe and preventing pollution of a facility environment. And

[0008]

In order to achieve the above object, a pressure-reducing device pressure-increasing purge gas introduction device according to the present invention comprises a supply pipe connecting a purge gas supply source and a pressure-reducing device, and a part of the supply pipe. a cooling means for cooling and trapping moisture in said purge gas, a heating device for purge heating the inside the supply pipe which is cooled by the cooling means, a detection means for detecting the temperature of the inner wall of the vacuum apparatus, Previous
Receiving the detection result from the detecting means, the purge gas
The temperature raising means so as to be higher than the inner wall temperature of the pressure device.
And control means for controlling the

[0009]

After passing through a cooling means such as a cold trap bath, the purge gas in the supply pipe is subsequently removed by the temperature raising means.
Raise the temperature. The temperature increasing means is a decompression device detected by the detecting means.
Based on the temperature of the inner wall of the device, the purge gas is
Raise the temperature to be higher than the temperature. This heated
When purge gas is introduced into the decompression device, the purge gas
The impurities adhering to the inner wall of the decompression device are evaporated and
I can care. Also, the purge gas that has been heated is supplied.
When passing through the supply pipe, the temperature difference between the inside and outside of the supply pipe is reduced, or the temperature inside the supply pipe is set to be equal to or higher than the external temperature to prevent dew condensation on the outer wall of the supply pipe.

It is preferable that the temperature raising means is arranged so as to raise the temperature of the supply pipe immediately after passing through the cooling means.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of a pressure-reducing device pressure increasing purge gas introducing device according to the present embodiment.

In FIG. 1, before and after a process chamber 10 for performing an etching step of a semiconductor process,
The load lock chamber 12 for carrying in and the load lock chamber 14 for carrying out are connected. Each of these chambers 1
Reference numerals 0, 12, and 14 decompress devices for forming an internal state under reduced pressure in a vacuum atmosphere, and vacuum pipes 16, 18, and 2, respectively.
0 and communicate with a vacuum pump (not shown). In addition, the entrance of the load lock chamber 12 for loading, the exit of the load lock chamber 14 for unloading,
Gates 12 and 14 are connected to each other, and can be opened and closed.
2, 24, 26, 28 are provided, and each chamber 10,
Both 12 and 14 can be independently sealed.

The pressure reducing purge gas introducing device is provided in each of the chambers 10, 12, and 14, and includes a purge gas supply source (not shown) and each of the chambers 10, 12, and 1.
4 is provided with a supply pipe 30 communicating with the pump 4, a cold trap bus 32 as a means for cooling the purge gas, and a sealed oil bath 34 as a means for raising the temperature of the purge gas.

The supply pipe 30 has branch pipes 30b, 30c and 30d at the end of the main pipe 30a.
The tips of 30c and 30d are connected to chambers 10, 12, and 14, respectively.
Connected to In addition, each branch pipe 30b, 30c, 30
In d, pipe opening / closing valves 36, 38, 40 which are individually opened / closed by control means (not shown), mass flow controllers 42, 44, 46 for adjusting the flow rate of the supply purge gas.
And filters 48, 50 and 52 for removing impurities. The filters 48, 50 and 52 are, for example, 0.01 μm.
Impurity particles having a particle size of m or more can be trapped.

The cold trap bath 32 is filled with, for example, liquid nitrogen as a cryogenic medium. Supply piping 3
A part of 0 is immersed in the liquid nitrogen filled in the cold wrap bath 32 and arranged. The length of the supply pipe 30 immersed in the liquid nitrogen may be any length, but at least a length sufficient for moisture in the purge gas passing through the supply pipe 30 to condense due to a temperature difference between the inside and outside of the pipe and separate from the purge gas.

The closed oil bath 34 is filled with oil as a heating medium, and the oil is supplied to the heat generating coil 34.
Heat is maintained at a constant temperature by a or the like. A part of the supply pipe 30 derived from the cold trap bus 32 is subsequently disposed in a closed oil bath 34.
Here, the temperature of the oil and the length of the supply pipe 30 arranged in the oil bath may be arbitrary, but at least the supply pipe 3
It is necessary to adjust so that the temperature of the purge gas within 0 can be raised to near normal temperature. In the present embodiment, the reason why oil was used as the heating medium is that the heat retention is higher than that of hot water, and the oil bath 34 was made closed.
This is to prevent the evaporated oil from scattering into the clean room and contaminating the equipment environment.

Next, the operation of the pressure-reducing device pressure-increasing purge gas introducing device will be described.

When a purge gas composed of an inert gas such as N ₂ gas is supplied at a predetermined pressure from a purge gas supply source (not shown) into the supply pipe 30, the purge gas is supplied to the supply pipe 30 disposed in the cold trap bus 32. In the portion of, the water contained due to the temperature difference between the inside and outside of the tube is dewed on the inner wall of the tube and separated. The moisture condensed on the inner wall of the pipe can be discharged from the drain discharge path (not shown) to the outside of the pipe. The supply pipe 3 in the cold trap bus 32
In part 0, the purge gas is cooled to a low temperature.

Subsequently, the purge gas reaches a portion of the supply pipe 30 arranged in the closed type oil bath 34, where the temperature of the purge gas is raised to near room temperature. Thereafter, the purge gas proceeds through the supply pipe 30, and the purge gas whose flow rate has been adjusted by the mass flow controllers 42, 44, 46 is supplied to each chamber 1 via valves 36, 38, 40 and filters 48, 50, 52.
0, 12, and 14. Filters 48, 50,
At 52, dust having a diameter of 0.01 μm or more mixed in the purge gas is removed. In the supply pipe 30 after passing through the closed type oil bath 34, the temperature of the purge gas is close to room temperature, so that there is no temperature difference between the inside and outside of the pipe, and therefore, there is no possibility that water droplets condense on the outer wall of the pipe.

Next, a procedure for loading and unloading a semiconductor wafer into and from the process chamber 10 will be described.

First, with the gates 22 and 26 provided at the entrance and exit of the loading load lock chamber 12 closed, the valve 36 of the supply pipe 30 is opened to supply a purge gas into the chamber 12, and the interior of the chamber 12 is purged. A pressure slightly higher than the atmospheric pressure is set by the purge gas. From this state, the gate 22 is opened, the semiconductor wafer is inserted into the load lock chamber 12, and the gate 22 is closed again. Since the inside of the load lock chamber 12 is slightly higher than the atmospheric pressure, there is no possibility that air or moisture flows into the chamber 12 during the operation of inserting the semiconductor wafer. After the above-described insertion operation, the valve 36 is closed to evacuate the load lock chamber 12 for carrying in, the valves 38 and 40 are also closed in the process chamber 10 and the load lock chamber 14 for carrying out, and each gate 24 is closed. , 28 are evacuated in a closed state.

After the evacuation, the gate 26 between the loading load lock chamber 12 and the process chamber 10 is opened, the semiconductor wafer is transferred into the process chamber 10, the gate 26 is closed again, and the semiconductor wafer is evacuated to a predetermined pressure. Later, the etching process is started. After completion of the etching process, the process chamber 10 and the load lock chamber 14 for unloading are set at substantially the same pressure, the gate 28 between them is opened, the semiconductor wafer is transferred into the load lock chamber 14 for unloading, and the gate is re-opened. Close 28.

Subsequently, a purge gas is supplied into the load lock chamber 14 for unloading by opening the valve 40, and the inside of the chamber 14 is set to a pressure slightly higher than the atmospheric pressure, and then the gate 24 is opened to unload the semiconductor wafer. . Again,
Since the inside of the load lock chamber 14 for carrying out is at a pressure slightly higher than the atmospheric pressure, no air or moisture flows into the chamber 14.

Here, when N ₂ gas is introduced to increase the pressure in each of the chambers 10, 12, and 14, the moisture in the N ₂ gas is previously cold-trapped, and the moisture is introduced into the chambers. Is reduced as much as possible, and the N ₂ gas is dried by being heated in the closed type oil bath 34. By introducing the N ₂ gas into the chamber, an action of blowing off impurities adhering to the inner wall of the chamber can be expected. As described above, both the action of reducing the supply of moisture into the chamber and the action of blowing off the impurities attached to the inner wall of the chamber can further reduce the evacuation time.

The present invention is not limited to the above-described embodiment. For example, a plasma device, an ashing device, a sputtering device, an ion implantation device, a semiconductor manufacturing process, etc. which require a decompression device in a semiconductor manufacturing process. Needless to say, the present invention can be applied to a pressure increasing purge gas introducing device of various pressure reducing devices used other than the above.

Further, as the temperature raising means, other than the closed type oil bath shown in the above-mentioned embodiment, a structure such as heating by a usual constant temperature bath or a band heater wound around a supply pipe may be adopted. .

Further, when the temperature of the persi gas is raised to a temperature higher than the inner wall temperature of the pressure reducing device by the temperature raising means, the impurities adhered to the inner wall of the pressure reducing device are evaporated by the high-temperature purge gas. Can be further enhanced. In this case, in particular, as shown by the imaginary line in FIG. 1, the detection result of the inner wall temperature of the process chamber 10 is input to the control device 100,
It is preferable that the control device 100 controls the oil temperature in the closed oil bath 34 to be higher than the chamber inner wall temperature.

[0029]

As described above, according to the present invention,
The purge gas in the feed pipe is cooled for moisture removal, decrease Ri by the heating device based on the detection result of the detecting means
Since the temperature was raised to be higher than the inner wall temperature of the pressure reducing device, it adhered to the inner wall of the pressure reducing device to evaporate impurities,
The dew condensation on the outer wall of the supply pipe can be eliminated, the pollution of the facility environment can be effectively prevented, and the exhaust of the introduced purge gas can be performed without causing moisture to adhere to the inner wall of the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a pressure-reducing device pressure increasing purge gas introducing device according to an embodiment of the present invention.

DESCRIPTION OF SYMBOLS 10 Process chamber 12 Load lock chamber for loading 14 Load lock chamber for unloading 16, 18, 20 Vacuum piping 22, 24, 26, 28 Gate 30 Supply piping 32 Bus for cold trap 36, 38, 40 Valve 42 , 44,46 Mass flow controller 48,50,52 Filter 100 Controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/302 H01L 21/205

Claims (1)

(57) [Claims] 1. A purge gas introduction device for introducing a purge gas into a decompression device to increase the pressure in the decompression device, comprising: a supply pipe communicating a purge gas supply source with the decompression device; and a part of the supply pipe. a cooling means for cooling and trapping moisture in said purge gas, a heating device for purge heating the inside the supply pipe which is cooled by the cooling means, a detection means for detecting the temperature of the inner wall of the vacuum apparatus, Upon receiving the detection result from the detection means, the purge gas is
The temperature raising means is set to be higher than the inner wall temperature of the pressure reducing device.
And a control means for controlling a stage .