JPH0282436A - Mass spectrograph - Google Patents

Abstract

PURPOSE:To make it possible to prevent adsorption or residence of a sample gas in an analytical tube and to accurately analyze a change in concentration of an object sample gas by installing a switching valve whose opening-closing time can be arbitrarily set at the tip or in the middle of a sampling piping through which a sample gas is taken. CONSTITUTION:A solenoid valve 3 whose opening-closing time can be controlled, a sampling tube 4, an analytical tube 6 and an operating exhauster 8 are connected to a sampling port 2 so that they are controlled by a control unit 9. A sampling gas 11 passes the sampling port 2 from a plasma 10 in a plasma generator 1 and then a solenoid valve 3, a gas sampling tube 4 and an orifice 5 to be introduced to an analitical tube 6 so that the sampling gas 11 is ionized and then detected. The opening and closing intervals of the solenoid valve 3 are controlled by a signal from the control unit 9 such that the valve 3 is opened and closed ordinally at a cycle of 0.1-1.0sec. Thereby, it is possible to analyze a change in concentration of the sampling gas in the chamber at a real time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to semiconductor manufacturing equipment that utilizes plasma, and particularly to a mass spectrometer suitable for gas analysis within a plasma chamber.

[Conventional technology]

Conventional plasma gas analyzers, often referred to as quadrupole lid analyzers (abbreviated as QMS), are heavy, and the connection method with the chamber is as shown in Fig. 2 in the literature. Gas was sampled using a barrier pull leak valve or gate valve and orifice. However, with these connection methods, if the pressure of the sample gas in the chamber is 10'Pa or more, the gas concentration will increase, which may cause it to adsorb to the inner wall of the sampling pipe or to remain in the QMS analysis pipe for a long time. It has been difficult to accurately analyze changes in gas concentration within the chamber.

[Problem to be solved by the invention]

In the above conventional technology, the only way to prevent gas adsorption to the sampling pipe is to shorten the length of the pipe as much as possible.
No consideration was given to the problem of the sample gas remaining in the analysis tube of the mass spectrometer, and there was a problem in that it was not possible to analyze the concentration change of the sample gas in the chamber in real time.

[Means to solve the problem]

The above object is achieved by providing an opening/closing valve whose opening/closing time can be arbitrarily set at the tip or midway of the sampling pipe for sampling the sample gas.

[Effect]

By setting the opening/closing cycle of the opening/closing pulp installed at the tip or midway of the sampling pipe to an arbitrary interval, the amount of sample gas introduced into the analysis tube of the mass spectrometer can be adjusted to a level that does not cause contamination by adsorption on the inner wall of the analysis tube, etc. can do.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. First, the configuration and operation of this embodiment will be explained with reference to FIG. A quadrupole mass spectrometer 7 is connected to a gas sampling port 2 provided on the side of the plasma generator 1, and a solenoid valve 3 whose opening/closing time can be controlled, a sampling tube 4, and an analysis tube are connected to the sampling port 2. 6 and an actuated exhaust device 8 are connected. The above devices are controlled by a control panel 9. The sampling tube 3 has an orifice 5
is built-in.

Next, the measurement method will be explained. Sample gas 11 is passed from plasma 10 in plasma generator 1 through sampling port 2 to electromagnetic valve 3, gas sampling pipe 4. It passes through the orifice 5, is introduced into the analysis tube 6, is ionized, and then detected. The opening and closing intervals of the solenoid valve 6 are controlled by signals from the control panel 9, and are normally opened and closed at a cycle of 0.1 to t0 seconds.

The measurement results are shown in the second factor. The solid line mass peak intensity 12 represents the change in peak intensity over time when the lower solenoid valve 3 is opened and closed periodically, and the dotted line mass peak intensity 13 indicates the state in which the solenoid valve 5 is open. This shows the change over time in the plasma generator 1, and is a measurement result when the gas pressure inside the plasma generator 1 is decreased over time. Looking at the change in the mass peak intensity when the solenoid valve 6 is open, shown by the dotted line, the change in the peak intensity relative to the change in gas pressure inside the plasma generator 1 is gradual, whereas the change shown by the solid line The change in peak intensity when the electromagnetic valve 5 is opened and closed periodically shows a change over time similar to the change in gas pressure.

〔Effect of the invention〕

According to the present invention, since it is possible to determine the adsorption and retention of the sample gas in the analysis tube, it is possible to accurately analyze the concentration change of the target sample gas.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention, FIG. 2 is a diagram showing the measurement results. 1... Plasma generator, 2... Sampling port, 6...' solenoid valve, 4... Sampling tube, 5... Orifice, 6...Analysis tube, 7... Quadrupole mass spectrometer, 8...operating exhaust system, 9...Control panel. 10...Plasma, 11...Sample gas. No. 7L￥]

Claims (1)

[Claims] 1. A mass spectrometer used for gas analysis in a chamber of a semiconductor manufacturing device using plasma, characterized in that a gas sampling mechanism connected to the chamber is provided with an opening/closing valve whose opening/closing interval can be set at any time. mass spectrometer.