JPH03213132A - gas mixer - Google Patents

Abstract

PURPOSE:To form the uniformed mixed state of a plurality of introduced gases by forming a dynamic structure having a complicated gas flow passage by the screw groove of a mixer housing and a rotary accelerator having a screw groove and rotated by a drive motor. CONSTITUTION:A plurality of gas introducing ports 24 respectively introducing gases of two or more kinds or two or more components are formed to a mixer housing 11 having a screw groove 12 provided to the inner peripheral surface thereof. A rotary accelerator 13 has a screw groove 14 at the same pitch as the screw groove 12 and a gas flow passage is formed between both screw grooves. Further, the rotary accelerator 13 is rotated by the motor shaft 16 connected to a drive motor 18 and the motor shaft 16 is held to the mixer housing 11 in a freely rotatable manner by a vacuum connection part 19. Furthermore, one mixed gas lead-out port 25 is formed at the position on the rotary axis of the rotary accelerator of the mixer housing 11 to guide a gaseous mixture to a gaseous mixture treatment apparatus. As a result, the uniform mixed state of a plurality of introduced gases can be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to thin film forming apparatuses, dry etching plasma apparatuses, etc., which require the handling of a mixed gas of two or more types or two or more component source gases and reactive gases. The present invention relates to a gas mixer that is used as an input to a gas processing device.

Conventional technology Conventionally, this type of mixed gas processing equipment mixes, for example, two or more gases or two or more components, generates plasma inside the equipment by high-frequency discharge, direct current discharge, etc., and uses the energy to generate gas. There are plasma devices that perform phase chemical reactions. There is also a photo-CVD device that selects light of an appropriate wavelength from light ranging from the ultraviolet region to the infrared region, and performs a gas phase chemical reaction using photochemical decomposition of introduced gas and light energy.

In any case, in this kind of gas-phase reaction apparatus that handles two or more types of gases, it is generally required that a uniform gas mixture is introduced when the gases are introduced into the apparatus.

Therefore, conventionally, as a first method, n types of introduction gases Ga, -, Gn are introduced into the gas phase reactor l from gas introduction pipes 2a to 2n of different routes, as shown in Fig. 3. There is a junction type gas mixer that integrates the two at one junction 3. This is the most commonly seen format, the % formula.
810, it is treated as prior art). As schematically shown in FIG. 4, n types of introduced gases Ga, .
The gases are introduced as they are from a to 5n, and a turbulent flow is generated using the pressure difference and flow rate change between the gas introduction pipe 5 and the gas phase reactor 4, and a homogeneous mixed gas can be obtained in the gas phase reactor 4. This is how it was done.

Furthermore, there is a third method as shown in FIG. This is a type developed and improved from the junction type, and includes a so-called buffer chamber containing a hollow body 7 in which a large number of passage holes 6 are formed between the junction 3 and the gas phase reactor l to complicate the passage route. 8. That is, an attempt is made to generate turbulent flow while the gas passes through a complicated path within the buffer chamber 8 to mix uniformly.

Problems to be Solved by the Invention However, according to the first method, different gases collide with each other within the junction 3, so even if they are mixed, it is difficult to create a uniform mixed state.

In the second method, the desired turbulence cannot be obtained due to slight fluctuations in the gas phase reactor 5 and the pressure of the introduced gas, and a uniform mixing state cannot be obtained.

In the third method, the degree of uniformity of the mixing state is higher than in the above two examples, but due to the complicated path, the buffer chamber 8
This may lead to deterioration of the conductance within the gas phase reactor, making it difficult to lead out the gas to the gas phase reactor l.

In other words, these conventional methods have drawbacks such as difficulty in obtaining a uniform gas mixture state, difficulty in introducing the mixed gas into the gas phase reactor, and deterioration of the conductance of the gas mixer. In particular, according to the conventional method, the gases are mixed and extracted using the pressure difference between the introduced gas pressure and the pressure inside the gas phase reactor, so the gas itself exhibits a dynamic turbulent flow state, but the gas mixer itself It will be used as a static container.

For this reason, controlling the gas mixing conditions uniquely deals with only the pressure difference, and it is necessary to empirically create a uniform mixing state by adjusting the physical size of the mixer itself, the thickness of the piping, etc. Become. In other words, a different gas mixer is used for each gas phase reactor, and is unique to each gas phase reactor.

Means for Solving the Problem A rotary accelerator having a thread groove having the same pitch as the thread groove and forming a gas flow path between both the thread grooves is provided in a mixer housing having a thread groove on the inner circumferential surface. A motor shaft rotatably held by a vacuum connection to the housing is connected to a rotary accelerator to be rotated by a drive motor, while two or more gases are introduced into the outer periphery of the mixer housing. A plurality of gas inlet ports were formed to guide the mixed gas to the mixed gas processing device, and one mixed gas outlet port was formed at a position on the rotary accelerator rotation axis of the mixer housing to lead the mixed gas to the mixed gas processing device.

The gas introduced into the mixer housing from the working gas inlet is led out to the mixed gas processing device from the mixed gas outlet via the gas flow path. At this time, when the rotary accelerator is rotated by the drive motor, the gas flow path formed by both thread grooves becomes dynamic, and the mixed gas passing therethrough is given a delivery pressure and has a flow velocity. Therefore, the delivery pressure due to the dynamic structure of the mixer itself is added to the pressure difference between the pressure of the introduced gas and the pressure inside the mixed gas processing device, so that the gas can be easily delivered to the mixed gas processing device. In addition, since the introduced gas itself becomes a turbulent flow and passes through a complicated gas flow path formed by both screw grooves, the mixing state becomes uniform.Secondly, given these mixing conditions and outlet pressure, the rotary This can be handled by appropriately controlling the rotation of the accelerator, and is dynamic and has no specificity to the mixed gas processing device to which it is connected.

Embodiment An embodiment of the present invention will be explained based on FIGS. 1 and 2. First, a hollow cylindrical mixer housing 11 is provided. A part of the mixer housing 11 has a thick wall, and the inner peripheral surface thereof has a thread groove 12 that constitutes a stator.
is formed.

A rotary accelerator 13 is provided inside the mixer housing ll. The rotary axle 13 has a smaller diameter than the thicker portion of the mixer housing 11, and has a threaded groove 14 formed on its outer periphery. This thread groove 1
4 has the same pitch as the thread groove 12 (details will be described later). Therefore, a space called a gas flow path 15 is formed between both thread grooves 12, 14 inside the mixer housing 11. Further, the rotary accelerator 13 is fixed to a motor shaft 16 with a screw 17, and is held in a cantilever state so as to be rotatable by a drive motor 18 provided outside the mixer housing 11. Here, the motor shaft 16 passes through a part of the mixer housing 11, and this part is held by a vacuum connection part 19. Vacuum connection part 19
consists of a non-lubricated bearing 20, a Wilson seal 21 and a cap 22. Here, 5US316 is used for all of these mixer housing 11, rotary accelerator 13, motor shaft 16, and non-lubricated bearing 20, and corrosion resistance is taken into consideration.

Furthermore, a gas inlet 24 and a gas outlet 25 are formed in the mixer housing 11 so as to be located on both sides of the rotary axle 13 . First, a plurality of gas inlet ports 24 are formed on the outer periphery of the mixer housing 11 in the vicinity of a position corresponding to the motor shaft 16, corresponding to the types of gases to be introduced. Further, the gas outlet 25 is connected to the mixer housing 11.
It is located at one end of the rotary axle 13 on the rotation axis of the rotary accelerator 13, and is connected to a gas phase reaction device (not shown). Note that the thread groove 12. The feeding direction of =14 is set to the gas outlet 25 side.

Here, the drive motor 18 is connected to the CP as shown in FIG.
The drive is controlled by a motor controller 27 controlled by U26. Further, the pressure of the gas introduced from the gas introduction port 24 is controlled by an introduced gas pressure Kamas flow controller 28.

In such a configuration, the introduced gases to be mixed are introduced into the mixer housing 11 from each gas inlet 24 under the control of the introduced gas pressure Kamas flow controller 28. Here, for example, the pressure on the primary side is 1.0
kg/co? , gas flow rate 15CCM, 30CCM
, 50ccM. Each gas introduced into the mixer housing 11 is
, 14, and is led out from the gas outlet 25 into the gas phase reactor as a uniform mixed gas.

At this time, since the rotary accelerator 13 is rotated by the drive motor 18, the introduced gas becomes turbulent and mixed in the dynamic gas passage 15 between the thread grooves 12 and 14.

In addition, since the groove is cut so that the feeding direction of the screw groove 14 is on the gas outlet 25 side, the turbulent mixed gas is reliably sent to the gas outlet 25 side with a flow velocity. According to experiments, when the pitch (same pitch) of thread grooves 12 and 14 was set to three types: 5mm, 10mm, and 12mm, the most stable flow velocity was obtained when the pitch was l'ommm. . Note that the distance between the thread grooves 12 and 14 (the gap between the gas passages 15) is 2 marks.

Experiments were conducted with three types, 3-barrel and 5-barrel, and the flow velocity was most stable with 3-barrel. Incidentally, the groove depth of the thread groove 12 was 5nvn, and the groove depth of the thread groove 14 was 3M.

Incidentally, the rotational speed control of the drive motor 18 is self-controlled by a CPU 26 having a block diagram configuration shown in FIG. That is, the predetermined mass flow output (inflow amount) obtained from the introduced gas pressure Kamas flow controller 28
and the vacuum level output obtained from the vacuum gauge 29 of the gas phase reactor are input into the CPU 26, the CPU 26 performs calculations, controls the motor controller 27 according to the calculation results, and controls the drive motor 1.
The number of rotations (rotational speed) of 8 will be controlled.

For example, argon and oxygen are each introduced at 1,100 yen each.
When CC was introduced into the mixer housing 11 at an inflow rate so that the degree of vacuum in the gas phase reactor was 10-'Pa, the rotation speed of the drive motor 18 was 380 to 530 rpm.
It is controlled within the range of . This is the main pump of the gas phase reactor (in this example, TG1 manufactured by Osaka Vacuum Co., Ltd.
The degree of vacuum in the gas phase reactor is determined by the pumping speed of the 800 turbo molecular pump) and the opening degree of the throttle valve.
This difference arises because the throttle valve controller 30 is simultaneously controlled by the CPU 26 (for this reason, the throttle valve controller 30 is also connected to the CPU 26). At this time, according to the output of the introduced gas pressure Kamas flow controller 28, the gas inflow amount is I
00ccy±2 CCM, which causes some wobbling, but this can be solved by more accurately finding and designing the dimensions of the stator and rotor in the gas mixer.

When plasma oxidation of an aluminum thin film was performed using a gas mixer as in this example, the in-plane variation in the thickness of the obtained aluminum oxide film was 2 ± 0.15%, and the same This is a marked improvement over the in-plane variation of 7% in the case of an aluminum oxide film obtained under the same plasma conditions in a gas phase reactor, confirming that the mixed gas was supplied uniformly. be.

Effects of the Invention As described above, the present invention provides a mixer housing having a threaded groove on the inner circumferential surface, and a drive motor having a threaded groove having the same pitch as the threaded groove to form a gas flow path between both threaded grooves. The rotary accelerator is rotated by the rotary accelerator, which creates a dynamic structure with a complex gas flow path, so multiple gases can be mixed uniformly and easily guided from the gas outlet into the mixed gas processing equipment. The system is dynamic and can be adapted to various mixed gas processing devices by appropriately controlling the rotation speed of the rotary accelerator by the drive motor, and is not unique to any particular mixed gas processing device. be able to.

[Brief explanation of drawings]

FIG. 1 is a sectional structural diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing a control system, and FIGS. 3 to 5 are schematic sectional views showing different conventional examples. 11...Mixer housing, 12...Thread groove, 13
...Rotary accelerator, 14...Thread groove, 15...
- Gas flow path, 16... Motor shaft, 18... Drive motor, 19... Vacuum connection part, 24... Gas inlet, 2
5...Gas outlet 1, . Figure 3

Claims (1)

[Claims] A mixer housing having a threaded groove on an inner peripheral surface, a plurality of gas inlets formed on the outer periphery of the mixer housing for respectively introducing two or more gases, and a threaded groove having the same pitch as the threaded groove. a rotary accelerator that forms a gas flow path between both threaded grooves; a drive motor connected by a motor shaft to rotate the rotary accelerator; and a vacuum connection that rotatably holds the motor shaft with respect to the mixer housing. and one mixed gas outlet formed at a position on the rotary accelerator rotation axis of the mixer housing to guide the mixed gas to a mixed gas processing device.