JPS62119434A - Monitor for dust inside gas piping - Google Patents

Abstract

PURPOSE:To enable the determination of the presence of dust and the amount thereof without sampling gas, by housing an optical system along in a box body connected in the middle of a gas piping while a counter in an electric system is set outside it. CONSTITUTION:A box body 11 is arranged in the middle of a gas piping 12 and a transparent tube 14 connected airtight between upper and lower ends of the gas piping 12. When a light from a light source 15 hits dust D in the transparent tube 14, the light is scattered by the dust D. The scattered light, first, is focused with a concave mirror 17 and then, reflected with a reflection mirror 18 to enter a light receiving section of a multiplying type photoelectric tube 19 which outputs electrical output signals corresponding to the presence and quantity of the scattered light to a counter 20 outside the box body 11. This eliminates problems of exhaust completely free from the sampling of gas thereby simplifying the design of construction.

Description

[Detailed Description of the Invention] [Summary] This is a gas piping dust monitoring device that can measure and monitor dust in the piping without sampling the gas in the gas piping.

[Industrial application field]

The present invention relates to an apparatus for monitoring dust in gas piping, and more specifically, to an apparatus for monitoring dust in gas used in semiconductor manufacturing processes for quality control.

[Conventional technology]

Various gases are used in the manufacturing of semiconductor devices.
These gases contain dust. Dust may already be contained in the gas at the gas supply source, or may be generated from pipe valves, joints, taps, etc. during use. If dust is included in the gas, it will hinder the production of semiconductor devices, so dust monitoring is required. Conventionally, when monitoring dust in gas piping, as shown in Figure 3, A discriminator 32 is provided in the middle of the pipe 31, and a switching mechanism of the discriminator 32 samples gas to a monitoring pipe 33, and the sampled gas is detected by a dust monitor device 34. Note that, except during this sampling, the gas in the gas pipe 31 is supplied to a processing chamber 35 in which semiconductor wafers are manufactured, for example.

[Problem that the invention seeks to solve]

However, according to this conventional example, the gas pressure in the gas pipe 31 is directly applied to the dust monitor device 34 during sampling, and in this case, the optical system and the electrical system are usually housed together in the dust monitor device 34. , parts that are sensitive to pressure, may be damaged or destroyed by gas pressure.

Furthermore, how to exhaust the sampling gas after the detection is completed is a serious issue because if the gas used is dangerous and toxic, it may affect human life.

In order to solve this problem, a monitoring module (view
According to this method, an attempt was made to install a peephole in a part of the gas pipe and attach a measuring instrument to the peephole to count the dust in the gas. There are restrictions on where the peephole can be installed, and there is also the problem of having to attach a measuring instrument to the peephole each time, so it cannot be said that this is a satisfactory monitoring method.

The present invention was created in view of these points, and an object of the present invention is to provide a device that can monitor dust in gas piping without sampling it.

[Means for solving problems]

Therefore, in the present invention, as in the embodiment shown in FIG.
By housing only the optical system within the housing 11 and installing the electrical system counter 20 outside the housing 11 using the multiplier type phototube 19, problems associated with conventional sampling can be solved. solve.

[Effect]

In the above device, if dust is present in the gas passing through the housing 11, the light from the light source 15 hits the dust and is scattered. This scattered light is detected by a multiplier phototube 19 in the optical system, and the electrical output signal of the phototube 19, which is the detection result, is output to a counter 20 outside the housing 11, thereby sampling the gas to determine the presence or absence of dust and the amount thereof. It can be measured without

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention.

In the figure, 11 is a housing disposed midway through the gas pipe 12, and the connection part with the gas pipe 12 is provided with lock screws 13a, 13.
Maintain the necessary airtightness by b. In addition, in a place where there is external light, this housing 11 has a light shielding property.

14 is a transparent tube connected between the upper and lower ends of the gas pipe 12. Here, if the transparent tube 14 is connected to the gas pipe 12 in an airtight manner, there is no need for the housing 11 to have an airtight structure. 15 is a light source such as a halogen lamp or a laser beam, and 16 is a light source 15. This is a convex lens installed between the transparent tube 14 and the transparent tube 14, and focuses light on the axial center position of the transparent tube 14. A concave mirror 17 is installed on the opposite side of the light source 15 with the transparent tube 14 as a boundary, and condenses the scattered light generated when it hits the dust D.

Reference numeral 18 denotes a reflecting mirror disposed obliquely between the transparent tube 14 and the convex lens 16, and a light projection window 18a through which light from the light source 15 passes is bored in the center of the reflecting mirror 18. Alternatively, the entire reflecting mirror 18 may be composed of a half mirror. Reference numeral 19 denotes a multiplier phototube disposed below the reflecting mirror 18. Of the above, the light source 15, the convex lens 16, the concave mirror 17, the reflecting mirror 18, and the multiplier phototube 19 constitute the optical system of the present apparatus, and are all housed within the housing 11. On the other hand, 20 is a counter that constitutes the electrical system of this device, and is electrically connected to the multiplier phototube 19 in the optical system and installed outside the housing 11.

In the first embodiment of the present invention, the illustrated transparent tube 14 is not provided,
Gas fills the housing 11. Dust contained in the gas is then detected as described below.

In the second illustrated embodiment of the invention, transparent tube 14
When the light from the light source 15 hits the dust D inside, the light is scattered by the dust D, and this scattered light is first focused by the concave mirror 17, then reflected by the reflector 18, and finally reflected by the multiplier phototube 19. enters the light receiving section. Multiplier phototube 1
9 outputs an electrical output signal corresponding to the presence or absence of scattered light and its amount to a counter 20 outside the housing 11. counter 2
0 measures and displays this output signal.

In this way, there is no difference in the dust detection function even when the gas in the gas pipe 12 passes only into the transparent tube 14 or when the gas in the casing 11 is filled.

FIG. 2 is a sectional view showing a third embodiment of the present invention, and in the figure,
The same reference numerals as in the previous figure indicate the same parts, 21 is the same type of housing with a different shape from the previous figure, 22 is a convex lens installed on the opposite side of the light source 15 with the transparent tube 14 as a boundary, and 23 is this convex lens 22.
24 is a light-shielding mask interposed between the convex lens 22 and the multiplier phototube 23, so that the direct light from the light source 15 is not directed to the multiplier phototube 23. Block entry.

This embodiment differs from the previous embodiment in that the optical system is assembled in such a way that the light scattered by the dust D is collected by a convex lens 22 and introduced into a multiplier phototube 23, but other effects are different. Basically the same.

Furthermore, regarding the arrangement of the optical system, the convex lens 22 and the multiplier phototube 23 of this embodiment may be installed at an angle to the direction of the light from the light source 15.

In this case, since direct light from the light source 15 does not enter, the light shielding mask 24 becomes unnecessary.

〔Effect of the invention〕

As described above, according to the present invention, since gas sampling is not performed, there is no need to consider the problem of exhaust gas.
Regarding the problem of the strength of parts against gas pressure, since only the optical system is housed in the housing and the electrical system is provided separately, the structural design can be simplified, especially in structures where gas only passes through the transparent tube. The effect will be greater. Furthermore, by adding a flow meter, quantitative measurements can be easily performed, and if this device is installed at multiple points in the middle of the piping, a comprehensive centralized control system can be created by integrating the electrical system.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a sectional view showing another embodiment of the invention, and FIG. 3 is a diagram showing a conventional example. In Figures 1 and 2, 11 and 21 are the housing, 2 is the gas pipe, 13a and 13b are the lock screws, 14 is the transparent tube, 15 is the light source, 16 and 22 are the convex lenses, 17 is the concave mirror, and 18 is the reflective mirror , 19 and 23 are multiplier phototubes, 20 is a counter, and 24 is a mask. Honjoro's sudden A row is shown in the first image of the masked prisoner.

Claims (2)

[Claims] (1) A housing (11) installed in the middle of the gas pipe (12)
, 21) houses an optical system for dust detection having a light source (15), a lens (16), and a multiplier phototube (19), and transmits an electrical output signal of the multiplier phototube (19) to the housing. (11, 21) A gas pipe internal dust monitoring device characterized in that measurement is performed using an external counter (20). (2) Connect the gas pipe located inside the optical tube to a transparent pipe (14
), and is configured to detect gas dust passing through the transparent tube (14).