JP2826479B2 - Gas supply device and operation method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas supply apparatus for supplying a corrosive gas and a gas having a low vapor pressure to a processing chamber for surface-treating a semiconductor substrate or the like, and a method of operating the same.

[0002]

2. Description of the Related Art Usually, a semiconductor substrate is housed in a processing chamber for forming an epitaxial film or a CVD film on a semiconductor substrate, and after evacuating the processing chamber, a gas is introduced to form a film on the semiconductor substrate. Was. The gas supply device for supplying the gas to the vacuum processing chamber needs to keep the gas flow rate constant and to stably maintain the gas pressure in the processing chamber.

FIG. 3 is a piping diagram showing an example of a conventional gas supply device. Conventionally, as shown in FIG. 3, for example, a gas supply device of this type controls a supply and cutoff of a gas to and from a processing chamber 8 evacuated by a vacuum pump 7 via a first on-off valve 6. Opening / closing valve 5, a mass flow controller 4 connected to the subsequent stage of the second opening / closing valve 5 via a pipe 9 and controlling the flow rate of supplied gas, 3
On-off valve 3.

FIG. 4 is a time chart for explaining the operation of the gas supply device of FIG. As shown in FIG. 4, the gas supply device supplies gas to the processing chamber 8 by opening the second on-off valve 5 and the third on-off valve 3 of FIG. Supply a constant flow of gas. Next, when the processing of the semiconductor substrate in the processing chamber 8 is completed, the third on-off valve 3 is closed to stop the gas supply.

After that, the inside of the mass flow controller 4 is evacuated for a certain time by the vacuum pump 7 through the second on-off valve 5 and the processing chamber 8. When the residual gas has been exhausted, the second on-off valve 5 is closed to complete the operation of the processing apparatus.

[0006]

In the above-described conventional gas supply apparatus, although a delay time is provided in the valve operation when the gas is shut off and the inside of the mass flow controller is evacuated, the first on-off valve, the processing chamber and the Since the gas is exhausted through the second on-off valve, there are mechanical parts having a long exhaust path and a large exhaust resistance, so that the exhaust in the mass flow controller is insufficient and gas remains inside. If the residual gas is a corrosive gas, the laminar flow element or nozzle in the mass flow controller, the nozzle,
There has been a problem that precision mechanism parts such as a diaphragm are corroded by residual gas, and it becomes impossible to precisely control the flow rate even if the parts do not operate.

Further, when the residual gas is a gas having a low vapor pressure, there is a problem that the residual gas is reliquefied in the mass flow controller and adheres as droplets to precision mechanism parts, causing malfunction. Further, since the exhaust operation of the mass flow controller is performed in series with the exhaust of the processing chamber, there is a disadvantage that one cycle time is required.

Accordingly, it is an object of the present invention to provide a gas supply apparatus capable of completely removing gas remaining in a mass flow controller when gas supply is stopped, constantly operating the mass flow controller stably, and further reducing the processing cycle time. It is to provide.

[0009]

SUMMARY OF THE INVENTION A feature of the present invention is that a second opening / closing valve for controlling the supply and shutoff of gas to a processing chamber evacuated by a vacuum pump via a first opening / closing valve, A gas supply device comprising: a mass flow controller connected to a stage subsequent to the on-off valve of No. 2 via a pipe and controlling a flow rate of the supplied gas; and a third on-off valve for supplying and shutting off the gas. A bypass pipe connecting the pipe and the vacuum pump to exhaust the residual gas into the mass flow controller by the vacuum pump when the supply of the gas is shut off, a fourth on-off valve provided in the middle of the bypass pipe , For mass flow controllers
Nitrogen supply device for supplying dry nitrogen through a fifth on-off valve
And a gas supply device comprising: Another feature of the invention is that
Processing evacuated by a vacuum pump via a first on-off valve
A second on-off valve for controlling gas supply and shutoff to the chamber;
If it is connected via a pipe to the second stage of the second on-off valve,
Mass flow controller for controlling the flow rate of the gas supplied to the
Third opening / closing for supplying and shutting off the gas to the controller
A valve and the mass flow controller when supply of the gas is shut off.
Before exhausting residual gas into the vacuum pump with the vacuum pump.
A bypass pipe connecting the pipe and the vacuum pump,
A fourth on-off valve provided in the middle of this bypass pipe
In the method of operating a gas supply device having
The second on-off valve and the third on-off valve are closed and the fourth on-off valve is closed.
Open the on-off valve and vacuum the inside of the mass flow controller.
An operation method of a gas supply device that exhausts gas by a pump.

[0010]

[0011]

Next, the present invention will be described with reference to the drawings.

FIGS. 1 (a) and 1 (b) are a piping system diagram and a time chart showing an embodiment of a gas supply device of the present invention. As shown in FIG. 1A, the gas supply device includes a bypass pipe 2 connecting the pipe 9 and the vacuum pump 7 to exhaust the residual gas into the mass flow controller 4 by the vacuum pump 7 when the supply of the gas is cut off. And a fourth on-off valve 1 provided in the middle of the bypass pipe 2. Otherwise, it is the same as the conventional example.

Next, the operation of the gas supply device will be described. First, as shown in FIG. 1B, when processing a semiconductor substrate in the processing chamber 8, the closed second on-off valve 5 and third on-off valve 3 are opened, and the fourth on-off valve 1 is closed. Closed and processing chamber 8
Is supplied with gas. Next, when the processing of the semiconductor substrate is completed, the second on-off valve 5 and the third on-off valve 3 close, the fourth on-off valve 1 opens, and the gas remaining in the mass flow controller 4 is evacuated through the bypass pipe 2. The gas is exhausted by the pump 7. Then, although not shown in the drawing, when the pressure is detected by a vacuum gauge attached to the bypass pipe 2 and the ultimate pressure is indicated, the fourth on-off valve 1 is closed.

As described above, by evacuating the gas through the bypass pipe 2 having a large conductance, the gas remaining in the mass flow controller 4 can be removed in less than 1/3 of the conventional time. Further, since the exhaust operation can be performed while the apparatus is stopped, the time for one cycle can be reduced.

In this embodiment, the vacuum pump 7 for evacuating the mass flow controller 4 is used in common with the vacuum pump 7 for evacuating the processing chamber 8. However, a dedicated vacuum pump may be provided.

FIG. 2 is a piping diagram showing another embodiment of the gas supply device of the present invention. As shown in FIG. 2, this gas supply device is provided with a nitrogen cylinder 11 for supplying dry nitrogen to the mass flow controller 4, and a fifth on-off valve for supplying and shutting off dry nitrogen. Other than that, it is the same as the above-mentioned embodiment.

The operation of this gas supply device is as follows. When exhausting the gas remaining in the mass flow controller 4, the fifth opening / closing valve 10 is opened and the vacuum pump 7 exhausts the gas while supplying dry nitrogen to the mass flow controller. Gas to be completely replaced with nitrogen. This is particularly effective when the vacuum ultimate pressure of the vacuum pump 7 is small.

[0018]

As described above, according to the present invention, a bypass pipe having a large conductance is directly disposed in a mass flow controller in order to exhaust gas remaining in the mass flow controller, and a vacuum is applied while feeding dry nitrogen as necessary. Exhaust gas can be completely removed by exhausting the mass flow controller through a bypass pipe with a pump. There is an effect that the controller can operate.

Further, since the exhaust operation of the residual gas by the mass flow controller can be performed in parallel in the processing chamber while the processing is stopped, there is also an effect that one processing cycle time can be shortened.

[Brief description of the drawings]

FIG. 1 is a piping diagram and a time chart showing an embodiment of a gas supply device of the present invention.

FIG. 2 is a piping diagram showing another embodiment of the gas supply device of the present invention.

FIG. 3 is a piping diagram showing an example of a conventional gas supply device.

FIG. 4 is a time chart for explaining the operation of the gas supply device of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 4th on-off valve 2 bypass pipe 3 3rd on-off valve 4 mass flow controller 5 2nd on-off valve 6 1st on-off valve 7 vacuum pump 8 processing room 9 piping 10 5th on-off valve 11 nitrogen cylinder

Claims (2)

(57) [Claims] 1. A second opening / closing valve for controlling supply and shutoff of a gas to a processing chamber evacuated by a vacuum pump via a first opening / closing valve, and a pipe disposed downstream of the second opening / closing valve. And a third on-off valve for supplying and shutting off the gas to a mass flow controller for controlling a flow rate of the gas supplied and connected to the gas supply device, the gas remaining in the mass flow controller when the gas supply is shut off. a bypass pipe for connecting the vacuum pump and the pipe for evacuating the gas in the vacuum pump, and a fourth on-off valve provided in the middle of the bypass pipe, the mass
Dry nitrogen into the flow controller through the fifth on-off valve
And a nitrogen supply device for supplying the gas. 2. A vacuum pump using a vacuum pump through a first on-off valve.
The second to control the supply and shutoff of gas to the exhausted processing chamber
And a second on-off valve and a pipe downstream of the second on-off valve via a pipe.
Control the flow rate of the gas connected and supplied
Supply and shutoff of the gas to the mass flow controller
A third on-off valve for shutting off the supply of the gas;
The residual gas is exhausted into the flow controller by the vacuum pump.
To connect the pipe and the vacuum pump to
Ipass pipe and a third pipe provided in the middle of this bypass pipe
In the operation method of the gas supply device having the on-off valve
And after the processing, the second on-off valve and the third on-off valve
Is closed and the fourth on-off valve is opened, and the mass flow control is opened.
The vacuum pump is evacuated by the vacuum pump.
Operating method of the water supply device.