JPH0426767A - Gas sampling monitor system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to gas sampling monitoring systems.

(Prior art) Conventionally, various processing gases have been used in processes such as chemical vapor deposition (CVD) and etching to form semiconductor films in semiconductor manufacturing, and analysis of reaction products, etc. Therefore, the processing gas is monitored in each manufacturing process.

FIG. 2 shows a conventional gas monitoring system, in which a differential pumping system device 12 is connected to a process chamber 10 in which film formation, etching, etc. are performed by CVD, and a differential pumping system device 12 is connected to a process chamber 10 in which film formation and etching are performed by CVD. A quadrupole mass spectrometer 14 for monitoring is connected. This quadrupole mass spectrometer 14 can measure the mass of substances contained in the gas supplied under reduced pressure from the differential pumping system device 12, thereby determining the mass of the gas components introduced into the process chamber 10. Monitoring is taking place.

(Problem to be Solved by the Invention) However, in the conventional gas monitoring system, the pressure is reduced, so although the mass spectrometer 14 can be used, the gas chromatograph device can only perform measurements in the pressurized state. The problem was that it was not possible to use As a result, the mass spectrometer 14 cannot distinguish between substances with the same mass; for example, water vapor (N20) with a mass of 8
It was not possible to distinguish between - and carbon oxide (Co).

Further, the differential pumping system configuration described above has a problem in that the system cost is high and manufacturing costs cannot be reduced.

The present invention was made in view of the above problems, and its purpose is to enable the use of a gas analyzer such as a gas chromatograph that can only be used in a pressurized state, and to reduce costs. The purpose of the present invention is to provide a gas sampling monitoring system.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, a gas sampling monitoring system according to the present invention includes a main flow path connected to a chamber and exhausting a processing gas under reduced pressure; A branch channel that is connected to the main channel so that the processing gas can be sampled; a pressurization channel that introduces pressurized gas to pressurize the branch channel; and a gas analysis of the pressurized processing gas. and a gas analyzer.

(Function) According to the configuration described in item 1, the gas exhausted along the main flow path also branches and flows through the branch flow path. The gas sampled in the branch channel is fed under pressure by pressurized gas introduced through the pressurized channel.

Furthermore, the process gas pressurized by the pressurized gas is forced into the gas analyzer in a pressurized state. Analysis of this pressurized gas can be performed using a gas chromatograph or the like.

(Example) Hereinafter, examples of the present invention will be specifically described with reference to the drawings.

FIG. 1 shows a gas sampling monitoring system according to an embodiment, and as shown in FIG.
A main flow pipe 16 functioning as an exhaust pipe is connected to a process chamber 10 in which film formation, etching, etc. are performed by chemical vapor deposition (chemical vapor deposition).

A vacuum pump (not shown) is connected to this main flow pipe 16, and this vacuum pump pumps process gas from several tens to several Tonnes along the main flow pipe 16 from inside the process chamber 10.
It is possible to exhaust the air in a reduced pressure state below rr.

1, the main flow pipe 16 is provided with a branch flow pipe 1-8 between the connecting portions 16A and 1-6B, and this branch flow pipe 18
The gas is branched from the main flow pipe 16.

And this branch flow path pipe] 8 has a two-way valve (valve) 20.
a, 20b, 20c, 20d and three-way valves 22a, 22b
is provided. A pressurized flow path pipe 24a is connected to one three-way valve 22a, and an analyzer introduction pipe 24b is connected to the other three-way valve 22b. In addition, the two-way valves 20a, 2
0d functions as a first valve that cuts off communication between the main flow pipe 26 and the branch flow pipe 18. Further, the three-way valve 22a functions as a second valve, and the three-way valve 22b functions as a third valve.

A three-way valve 26a is provided in the pressurized flow path pipe 24a.

26b is provided, and a pressurizing means 28 is connected to this pressurizing flow path pipe 24a, and this pressurizing means 28 pumps a pressurized gas such as nitrogen (N2) gas under pressure to the pressurizing flow path pipe 24a. do. At this time, the gas pressure is set to be higher than atmospheric pressure. Further, the analyzer introduction pipe 24b includes two-way valves 26c, 2
6d is connected, and a gas chromatograph device 30 as a gas analyzer is connected to this analyzer introduction pipe 24b.
The gas introduced into the branch flow path pipe 18 is supplied to the gas chromatograph device 30 in a pressurized state.

Further, in the embodiment, a pressure gauge 32 for measuring the pressure inside the branch flow pipe 18 is provided between the three-way valves 22a and 22b of the branch flow pipe 18, and a pressure gauge 32 is provided near the pressure gauge 32. A 10-shaped trough tube 18A is formed, and a cooling section 34 capable of supplying liquid nitrogen is arranged to accommodate the 1.8A trough 10-shaped tube. Therefore, it is also possible to temporarily trap the gas by using liquid nitrogen.

The embodiment has the above configuration, and during each process, the gas after being introduced into the process chamber 10 is driven by a pump (not shown) to the main flow path 100 and the branch flow path 200 (not shown).
It will be exhausted through.

Then, when monitoring the gas, the two-way valves 20a and 20d of the branch flow path pipe 8 are closed and the gas in a reduced pressure state is temporarily sampled. At this time, trap U-shaped tube 1
．． 8a, the reaction products in the gas can be reliably cold-trapped. Next, the two-way valves 26a, 26b and the three-way valve 22a in the middle of the pressurized flow path pipe 24a are opened to supply nitrogen gas (N
2) is introduced, and the branch flow path pipe 18 between the three-way valves 20a and 20 is brought into a normal pressure state. Subsequently, the three-way valve 22b
and a two-way valve 26c in the middle of the analyzer introduction pipe 24b.

26d is opened to form a pressure feeding channel 300, and the processing gas is introduced into the gas chromatograph apparatus 30 while being pressurized with the nitrogen gas. In the above case, the pressure in the pressurized channel 300 is monitored by the pressure gauge 32, and is set to an optimal pressure, for example, 1 to 2 kg/c♂.

The gas chromatograph device 30 has a separation tube, and substances in the gas are identified based on the difference in movement speed through the separation tube, and quantitative analysis is performed from the peaks of the chromatogram. Therefore, it is difficult to identify substances with the same mass number, for example, water vapor (N2
0) and -carbon oxide (CO).

In the above embodiment, the sampled gas is introduced only into the gas chromatograph device 30, but other analyzers such as a mass meter are connected together with the gas chromatograph device 30, and gas is supplied to these analyzers and other analyzers are introduced. The analyzes may be performed simultaneously.

In addition, gas is trapped in the trap U-shaped pipe 18A by the liquid nitrogen introduced into the cooling section 34, and the gas is trapped in the trap U-shaped pipe 18A.
It is also possible to remove the separation flow path pipe 18 from the connecting portions 16A and 16B of the analyzer and connect it to the gas chromatograph device 30 or other analyzer.

Note that the number and arrangement of the valves are not limited to those in the above embodiments, and various combinations can be applied.

[Effects of the Invention] As explained above, according to the present invention, a branch flow path branched from the main flow path is provided, a pressurized flow path is provided in this branch flow path via a valve, and the flow path is introduced into the process chamber. After branching the gas into the branch flow path, the gas is guided to the gas chromatography device under pressure via the pressurized flow path, making it easy to perform gas chromatography and performing qualitative and quantitative analysis. has dramatically improved, making it possible to identify even substances with the same mass number, for example.

Sampling also has the advantage of reducing manufacturing costs since it does not utilize an expensive differential pumping system.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a gas sampling monitoring system according to an embodiment of the present invention, and FIG. 2 is a diagram showing the configuration of a conventional gas monitoring system. DESCRIPTION OF SYMBOLS 10... Process chamber, 12... Differential exhaust system device, ]6... Main flow pipe, ]8... Branch flow pipe, 20.26... Two-way valve, 2
2... Three-way valve, 24a, 24b... Pressurized flow path pipe, 2
8... Pressurizing means, 30... Gas chromatograph device, 34... Trap section, 100... Main channel, 200...
... Branch flow path, 300... Pressurized flow path.

Claims (1)

[Claims] (1) A main channel that is connected to the chamber and exhausts the processing gas under reduced pressure; A branch channel that is connected to the main channel so that the processing gas can be sampled; and a pressurized gas that pressurizes the branch channel. 1. A gas sampling monitoring system comprising: a pressurized flow path for introducing the pressurized process gas; and a gas analyzer for performing gas analysis of the pressurized process gas.