JPS5836738B2 - Katsuseigasbun Atsusokutei Souchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to an apparatus for measuring the degree of vacuum of active gas.

Conventionally, it has been difficult to measure active gases over a wide range of vacuum variations.

For example, in the ionization vacuum gauge often used for gas measurement,
When attempting to measure active gas, the active gas was absorbed by the hot filament or the wall of the measurement bulb, resulting in large fluctuations in the measured values, making it impossible to measure the degree of vacuum with good reproducibility.

Additionally, diaphragm vacuum gauges can measure the absolute positive value of a gas regardless of the gas, but they have drawbacks such as not being able to measure in high vacuum, and the life of the diaphragm being shortened by corrosive gases such as halogens. Ta.

Unfortunately, other vacuum gauges had similar drawbacks.

In the present invention, active gases such as oxygen and halogens are
” This device is capable of measuring with good reproducibility over a range from Torr to 10 −3 Torr, and an example thereof will be explained based on the attached drawings.

As shown in FIG. 1, a primary ion generator 1 generates ions to become a primary ion beam.

At this time, an inert gas such as He or Ar is used as the primary ion species.

The created ions are accelerated by applying an extraction potential to the extraction electrode and guided to the primary ion focusing section 2.

The primary ion focusing section 2 focuses ions into an ion beam, and by changing the beam diameter, the current density can be changed.

The target section 3 is connected to a vacuum section where an active gas to be measured exists, and the active gas is introduced from the vacuum section.

The target m3 includes an active gas and is composed of a target holder and a target.

The target can be changed by rotating the target holder without breaking the vacuum (from external forces).

The target is made of a metal or a semiconductor (metal or semiconductor), and the secondary ions generated by the impact of the target with secondary ions are efficiently guided to the secondary ion detection unit 5 by the secondary ion convergence unit 4 .

The secondary ion detector 5 detects secondary ions as an amount of current.

In this way, when the target is sputtered with primary ions, a new target surface always appears, and even if the target surface changes due to the active gas, the present invention cannot accurately measure the degree of vacuum of the active gas. can.

Slits are provided between the secondary ion focusing section 4, the secondary ion detecting section 5, and the target section 3, and between the primary ion generating section 1, the primary ion focusing section 2, and the target section 3 to perform differential pumping.

An embodiment of the device of the invention is shown in FIG.

In the figure, 7 is a PIG ion source serving as a primary ion generating section, which uses Ar as the primary ion species.

The accelerating voltage is 500V to 12KV.

Reference numeral 8 is an Einzel lens, and reference numeral 9 is an electrostatic quadrupole lens, which constitute a primary ion convergence section that changes the current density of primary ions.

The current value is 10-9 to 10-6 A, and the current density of primary ions can be varied from 10-5AX to 10-7 people/d.

The current density can be changed by one digit using a switching dial.

10 is the exhaust system, 11 is the target, and the target is A.
A', Fe. Ni and Si are used, and it is attached to a rotatable target holder 12.

13 is a target conversion dial, and 14 is a secondary ion extracting electrode for extracting secondary ions generated by the impact of primary ions, which constitutes a secondary ion focusing section.

15 is a Faraday cage for detecting secondary ions.

As shown in FIG. 1, slits are provided for differential evacuation, and the primary ion generating section, primary ion focusing section, and secondary ion detecting section are evacuated by a diffusion pump or a rotary pump.

In the apparatus of the present invention, as shown in FIG. 3, the intensity of secondary ions generated in the active gas atmosphere changes depending on the degree of vacuum of the active gas.

As is clear from this figure, there is a region where the secondary ions change almost linearly as the degree of vacuum increases.

This range is about one digit in degree of vacuum.

By changing the current density of primary ions, the straight line portion moves in parallel as shown in the figure.

Therefore, by changing the current density of primary ions, the degree of vacuum of the active gas can be determined over a wide range.

As described above, according to the apparatus shown in FIG. 1.2, when a certain current density changes, the degree of vacuum of the active gas can be easily determined over a wide range by measuring secondary ions.

In other words, if the current density is changed over a wide range, the degree of vacuum can be easily measured over a wide range.

Furthermore, by changing the target by rotating the target holder, it is possible to select an appropriate target material depending on the gas to be measured.

Furthermore, even if the target is deformed due to sputtering by primary ions, a new surface can be used, extending the life of the vacuum gauge.

By differentially pumping the target part, the primary ion generation part, primary ion focusing part, secondary ion focusing part, and secondary ion detection part operate stably even when the vacuum part to be measured has a vacuum level of 10-3 Torr. .

As described above, according to the present invention, the vacuum level of active gas can be easily measured over a wide range, and this invention greatly contributes to the measurement of the degree of vacuum of active gas.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an active gas vacuum measuring device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram of the structure of the device,
FIG. 3 is a diagram showing the relationship between secondary ion strength and oxygen gas mocha using current density as a parameter. 2...Primary ion focusing section, 3...Target section, 5...Secondary ion detection section, 11...
····target.

Claims (1)

[Claims] 1. A variable current density ion source that uses an inert gas as the primary ion species and can change the current density of the primary ions, a target portion made of a metal or a semiconductor, and in which an active gas as a component to be detected is present; means for guiding secondary ions generated when a target is bombarded with primary ions to a detection section using a lens system, and the degree of vacuum of the active gas is measured by measuring the secondary ions at the detection section. An active gas vacuum measurement device featuring: