JP7200166B2 - Mixed gas supply device and method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a mixed gas supply apparatus and method, and more particularly to an apparatus and method for supplying a mixture of a plurality of gases at a predetermined flow rate ratio.

In the field of semiconductor manufacturing, various special material gases are used, for example, a mixed gas of trichlorosilane (TCS) and hydrogen (H2) is used to epitaxially grow crystals on wafers. It is desirable that such a mixed gas be manufactured and supplied in a state where the mixing ratio is maintained even if the amount used fluctuates.

As such a technique, for example, a plurality of gas supply paths provided with pressure control valves, flow rate control valves, and shutoff valves are merged, connected to a buffer tank equipped with a pressure gauge, and the pressure in the buffer tank is adjusted accordingly. A mixed gas supply apparatus has been proposed that controls the opening and closing of shutoff valves in each gas supply path by means of a gas supply line (see Patent Document 1).

In addition, the main gas flow path provided with the flow rate detection means and the pressure adjustment section and the additive gas flow path provided with the flow rate adjustment means are connected, and based on the flow rate of the main gas detected by the flow meter, the addition A mixed gas supply device has been proposed in which a flow rate adjusting means controls the flow rate of the gas and a pressure adjusting section adjusts the pressure of the main gas according to the pressure of the additive gas (see Patent Document 2).

Japanese Patent No. 3863644 Japanese Patent No. 5557827

However, in the invention described in Patent Document 1, a buffer tank is provided to accumulate pressure in order to stabilize the flow rate and pressure of gas, and it is possible to meet the demand for gas mixing without using high-pressure gas equipment. I wasn't able to.

Also, in the invention described in Patent Document 2, the pressure regulating portion is essential as a configuration, and the pressure loss in the pressure regulating portion is large, so the raw material gas cannot be handled at a low pressure.

Therefore, the present invention is a mixed gas supply that can mix a plurality of source gases while maintaining a constant mixing ratio regardless of the flow rate without using high-pressure gas equipment, and can supply the mixed gas to consuming equipment while maintaining a low pressure. It is an object to provide an apparatus and method.

In order to achieve the above object, a mixed gas supply apparatus of the present invention is a mixed gas supply apparatus for supplying a plurality of raw material gases mixed at a predetermined ratio, comprising a plurality of raw material gas supply paths and each raw material gas a gas merging section for merging a plurality of source gases supplied from the supply paths to form a mixed gas; and a mixed gas supply path for supplying the mixed gas to a user, wherein one of the source gas supply paths is Each branched path is provided with a flow meter, and the other source gas supply path is similarly branched into a plurality of paths, each branched path is provided with a flow rate controller, and the flow rate controller is provided with a corresponding A signal indicating a flow rate ratio obtained by dividing the detected flow rate by the upper limit of the measurable flow rate of the flow rate measuring device according to the detected flow rate. to the corresponding flow rate regulator, and the flow rate regulator, upon receiving the signal, obtains the flow rate of the source gas by multiplying the upper limit of the adjustable flow rate of the flow rate regulator by the flow rate ratio When the flow rate detected by the flow meter provided in one branch of the raw material gas supply route exceeds a preset first flow rate, the raw material gas in the adjacent branch route begins to flow. , the flow rate of the raw material gas in the adjacent branch path is cut off when the flow rate falls below a preset second flow rate which is smaller than the first flow rate .

Further, in order to achieve the above object, a mixed gas supply method of the present invention is a mixed gas supply method for supplying a plurality of raw material gases by mixing them in a predetermined ratio, wherein the plurality of raw material gases are supplied to each raw material gas supply path. , one of the source gas supply routes is branched into a plurality of branches, each branch route is provided with a flow meter, and the other source gas supply routes are similarly branched into a plurality of branches, and the flow rate is adjusted in each branch route. a device for supplying one raw material gas through the flow meter, and using an output signal based on the flow rate detected by the flow meter as an input signal to adjust the flow rate of the other raw material gas with a corresponding flow regulator. When the flow rate detected by the flow rate measuring device provided in one of the branched paths of the raw material gas supply path exceeds a preset first flow rate, the raw material gas in the adjacent branched path is started to flow, When the flow rate falls below a preset second flow rate that is less than the first flow rate, the flow of the raw material gas in the adjacent branched path is cut off, and a plurality of raw material gases are merged to form a mixed gas.
It is characterized by

According to the first mixed gas supply apparatus of the present invention, the flow rate of the second raw material gas is adjusted with respect to the flow rate of the first raw material gas by the measurement upper limit value of the flow meter and the adjustment upper limit value of the flow regulator. Since the raw material gases can be determined and mixed, a plurality of source gases can be mixed while maintaining a constant mixing ratio regardless of the flow rate, and the mixed gas can be supplied to the consuming equipment at a low pressure.

Further, according to the second mixed gas supply device of the present invention, when a large flow rate of mixed gas that cannot be supplied by a single flow meter and flow regulator is required, a plurality of devices are connected in a multistage manner. can be supplied by

1 is a system diagram of a mixed gas supply device showing a first embodiment of the present invention; FIG. 4 is a graph showing the relationship between the flow rate of each raw material gas and the mixing ratio of the mixed gas supply device. FIG. 4 is a system diagram of a multi-stage mixed gas supply device showing a second embodiment of the present invention; 4 is a graph showing the transition of the gas flow rate flowing into each first gas branch path as the flow rate of the first source gas increases in the multistage mixed gas supply apparatus of FIG. 3 ; 4 is a graph showing the transition of the gas flow rate flowing into each first gas branch path as the flow rate of the first source gas decreases in the multi-stage mixed gas supply apparatus of FIG. 3 ; 10 is a graph showing the transition of the flow rate of gas flowing into each first gas branch path as the flow rate of the first source gas increases in another multistage mixed gas supply device. 10 is a graph showing transition of the flow rate of gas flowing into each first gas branch path as the flow rate of the first source gas decreases in another multi-stage mixed gas supply device. FIG. 4 is a system diagram of a mixed gas supply device showing a modified example of the present invention;

FIG. 1 is a system diagram of a mixed gas supply device 11 showing a first embodiment of the present invention. In this embodiment, a case will be described in which a mixed gas obtained by diluting trichlorosilane (TCS) with hydrogen (H ₂ ) to 20% is supplied.

The mixed gas supply device 11 supplies a first gas supply path 13 extending from a TCS supply section 12 that supplies trichlorosilane (TCS), which is a first source gas, and hydrogen (H ₂ ), which is a second source gas. A _second gas supply route 15 extending from the H2 supply unit 14, and a mixed gas supply route 18 for supplying a mixed gas of TCS and H2 to a consumption facility 16 that uses the mixed gas. The first gas supply path 13 and the second gas supply path 15 join at a junction 17 and are connected to a mixed gas supply path 18 .

A temperature adjustment device 12a is attached to the TCS supply unit 12 to keep the supplied TCS at a predetermined temperature. If the vapor pressure is 0.2 MPa or more, it will be treated as a high-pressure gas facility. The temperature is adjusted at 50° C., which is 183 MPa.

The first gas supply path 13 is provided with a mass flow meter 19 (MFM), which is a flow meter, and a first cutoff valve 20 capable of shutting off the gas flow. A mass flow controller 21 (MFC), which is a regulator, and a second shutoff valve 22 capable of shutting off the gas flow are provided.

The confluence section 17, the mass flow meter 19, the first shutoff valve 20, the massflow controller 21, and the second shutoff valve 22 are each arranged inside the constant temperature bath 23 to keep the internal gas temperature constant. is configured as

For the mass flow meter 19, an upper limit value (measurement upper limit value) Hm of the flow rate that can be measured, called a full scale, and a lower limit value (measurement lower limit value) Lm of the flow rate at which measurement accuracy is guaranteed are predetermined. In this embodiment, the mass flow meter 19 with the measurement upper limit Hm of 50 L/min is adopted. Even for a model, it is about 0.5%.

Similarly, for the mass flow controller 21, an upper limit of adjustable flow rate (adjustment upper limit) Hc called full scale and a lower limit of flow rate (adjustment lower limit) Lc for which adjustment accuracy is guaranteed are set in advance. fixed. In the present embodiment, the TCS is diluted to 20%, so the mass flow controller 21 with 200 L/min as the adjustment upper limit Hc is employed. Similarly to the mass flow meter 19, the adjustment lower limit Lc is about 2% of the adjustment upper limit Hc for general models, and about 0.5% for high-precision models.

The mass flow meter 19 is electrically connected to each of the mass flow controller 21, the first shut-off valve 20 and the second shut-off valve 22 so as to be able to transmit information. It is set to convert the gas flow rate L1 into a voltage signal S (output signal) in the range of 0 to 5 V according to the flow rate ratio obtained by dividing the gas flow rate L1 by the measurement upper limit value Hm, and then send the voltage signal S (output signal).

That is, S=5·L1/Hm. For example, when the flow rate of TCS measured by the mass flow meter 19 is 40 L/min, the voltage signal S is 4V. At this time, the pressure of the TCS in the first gas supply path 13 was 0.183 MPa on the upstream side of the mass flow meter 19, but on the downstream side of the mass flow meter 19, it decreased to 0.18 MPa due to pressure loss in piping and the like. Become.

The mass flow controller 21 is formed to adjust the flow rate of the second gas supply path 15 according to the voltage signal S (input signal) received from the mass flow meter 19, and the flow rate L2 adjusted thereby is the adjustment upper limit. It is set to a value obtained by multiplying the value Hc by a flow rate ratio corresponding to the maximum value 5V of the voltage signal S.

That is, L2=Hc·S/5. Therefore, when the voltage signal S is ₄ V, the flow rate of H2 is adjusted to 160 L/min. At this time, the pressure of H2 was 0.25 MPa on the upstream side of the mass flow controller 21 in the _second gas supply path 15, but on the downstream side of the mass flow controller 21, it became the mixed TCS supply pressure ( 0.18 MPa in this embodiment).

_In this way, the ratio of TCS and H2 fed into the confluence section 17 is L1/L2 ₌ Hm/Hc. flow rate can be adjusted.

In addition, the first shutoff valve 20 and the second shutoff valve 22 each receive a voltage signal S when the flow rate L1 measured by the mass flow meter 19 reaches the measurement upper limit value Hm or falls below the measurement lower limit value Lm. , the valves are closed to cut off the gas flows in the first gas supply path 13 and the second gas supply path 15, respectively.

FIG. 2 is a graph showing the relationship between the flow rate of each raw material gas and the mixing ratio by the mixed gas supply device 11 in the first embodiment. It shows the results of measuring the gas flow rate in each path when it is changed.

As shown in FIG. 2, the flow rate L1(t) of the first gas supply path 13, the flow rate L2(t) of the second gas supply path 15, and the flow rate L3(t) of the mixed gas supply path 18 at time t , it can be seen that L3(t) = L1(t) + L2(t) holds in the range where the flow rate is constant, and L2(t) = 4 L1(t) .

Therefore, the mixing ratio of TCS and H2 is L1( _t ):L2(t)=20%:80%=Hm:Hc. It can be seen that it is determined by the relationship with the adjustment upper limit value Hc.

As described above, according to the mixed gas supply apparatus 11 of the present invention, the flow rate L2 of H2 as the second source gas is set to the upper measurement limit Hm of the mass flow meter 19 with respect to the flow rate L1 of TCS as the first source gas. and the adjustment upper limit value Hc of the mass flow controller 21, so that a plurality of raw material gases can be mixed while maintaining a constant mixing ratio regardless of the flow rate, and the mixed gas can be supplied to the consuming equipment at a low pressure. be possible.

Further, even if the first raw material gas flows through the first gas supply path 13 at a flow rate outside the range between the upper measurement limit Hm and the lower measurement limit Lm of the mass flow meter 19, the first gas supply path 13 is closed by the first shutoff valve. 20 and the second gas supply path 15 are shut off by the second shutoff valve 22, so that the gases can be mixed only when the mass flow meter 19 can accurately measure them, and a constant mixing ratio can be maintained. can.

FIG. 3 is a system diagram of a mixed gas supply device 30 showing a second embodiment of the present invention. In this embodiment, a plurality of mass flow meters and mass flow controllers are connected in multiple stages when a large flow rate of mixed gas that cannot be supplied by a single mass flow meter and mass flow controller is required in a consumer facility. .

As shown in FIG. 3, the multi-stage mixed gas supply device 30 in this embodiment differs from the first embodiment in the configuration inside the constant temperature bath 23, and there are three routes for mixing TCS and H ₂ . They are arranged in stages and in parallel.

First gas branch paths 13a, 13b, and 13c extend from the first gas supply path 13, and second gas branch paths 15a, 15b, and 15c extend from the second gas supply path 15, respectively.

The first gas branch path 13a and the second gas branch path 15a are connected to the mixed gas supply path 18 at the confluence portion 17a. , and the first gas branch line 13c and the second gas branch line 15c are connected to the mixed gas supply line 18 at a junction 17c.

In the mixed gas supply path 18, the confluence portion 17b is arranged upstream of the confluence portion 17a, and the confluence portion 17c is arranged upstream of the confluence portion 17b.

Mass flow meters 19a, 19b, and 19c are attached to the first gas branch paths 13a, 13b, and 13c, respectively, and mass flow controllers 21a, 21b, and 21c are attached to the second gas branch paths 15a, 15b, and 15c, respectively. is installed. The first gas branch path 13a has a first on-off valve 31 upstream of the mass flow meter 19a, and the first gas branch path 13b has a second on-off valve 32 upstream of the mass flow meter 19b. A third on-off valve 33 is attached to the path 13c upstream of the mass flow meter 19c.

The mass flow meters 19a, 19b, and 19c each have the same full-scale measurement upper limit value Hm, and the mass flow controllers 21a, 21b, and 21c each have the same full-scale adjustment upper limit value Hc. there is

The mass flow meter 19a is electrically connected to each of the mass flow controller 21a and the second on-off valve 32 so as to be capable of transmitting information. is converted into a voltage signal Sa in the range of 0 to 5 V according to the ratio to the upper measurement limit Hm and sent.

The mass flow meter 19b is electrically connected to each of the mass flow controller 21b and the third on-off valve 33 so as to be capable of transmitting information. is converted into a voltage signal Sb in the range of 0 to 5 V according to the ratio to the upper measurement limit Hm and sent.

The mass flow meter 19c is electrically connected to the mass flow controller 21c so as to be able to transmit information. is set to be converted into a voltage signal Sc in the range of 0 to 5 V according to the voltage and sent.

The mass flow controller 21a is configured to adjust the flow rate of the second gas branch path 15a according to the voltage signal Sa received from the mass flow meter 19a, and the flow rate L2a thus adjusted is equal to the adjustment upper limit value Hc. It is set to an amount obtained by multiplying the maximum value of 5 V of the signal S by a ratio.

The mass flow controller 21b is configured to adjust the flow rate of the second gas branch path 15b according to the voltage signal Sb received from the mass flow meter 19b, and the flow rate L2b thus adjusted is equal to the adjustment upper limit value Hc. It is set to an amount obtained by multiplying the maximum value of 5 V of the signal S by a ratio.

The mass flow controller 21c is configured to adjust the flow rate of the second gas branch path 15c according to the voltage signal Sc received from the mass flow meter 19c, and the flow rate L2c thus adjusted is equal to the adjustment upper limit value Hc. It is set to an amount obtained by multiplying the maximum value of 5V of the signal Sc by a ratio.

Regarding the opening and closing operation of the on-off valve in a multi-stage mixed gas supply system, if the opening and closing setting of the next-stage on-off valve is controlled with a single threshold value, the flow rate fluctuation will increase when opening and closing, and the concentration fluctuation will occur. Flow rate fluctuations can be reduced by setting the time thresholds separately.

Specifically, the second on-off valve 32 performs self-control of the device up to 80% of the voltage signal Sa, and when the voltage signal Sa received from the mass flow meter 19a exceeds 80% (4 V) of the maximum value of 5 V, the second on-off valve 32 It is set to open the on-off valve 32 and close the valve when the voltage signal Sb falls below 20% (1 V) of the maximum value.

The third on-off valve 33 performs self-control of the device up to 75% of the voltage signal Sb, and opens the valve when the voltage signal Sb received from the mass flow meter 19b exceeds 75% (3.75 V) of the maximum value of 5 V, and the voltage The valve is set to close when the signal Sc falls below 25% (1.25 V) of the maximum value.

The mixed gas is supplied by the multistage mixed gas supply device 30 as follows.

When the first on-off valve 31 is opened and TCS is supplied from the TCS supply unit 12 to the first gas supply path 13, TCS first flows into the first gas branch path 13a of the first stage, and the mass flow meter 19a , and sends a voltage signal Sa.

When the mass flow controller 21a receives the voltage signal Sa, the mass flow controller 21a causes the flow rate of H2 corresponding to the voltage signal Sa to flow from the H2 supply unit 14 to the _second gas branch path 15a, so that _TCS and H2 join. The mixed gas is mixed in the portion 17 a and flowed to the mixed gas supply path 18 , and supplied to the consumption facility 16 via the mixed gas supply path 18 .

Further, when the flow rate of TCS flowing into the first gas branch path 13a reaches 80% of the upper measurement limit Hm of the mass flow meter 19a, the second on-off valve 32 is opened in response to the voltage signal Sa. It also flows into the second-stage first gas branch path 13b.

When TCS flows through the first gas branch path 13b, the mass flow controller 21b measures the flow rate of TCS and sends a voltage signal Sb. When the mass flow meter 19b receives the voltage signal Sb, the mass flow meter 19b causes the flow rate of H2 corresponding to the voltage signal Sb to flow from the H2 supply unit 14 to the _second gas branch path 15b, so that the _TCS and H2 join. The gas is also mixed in the portion 17b and flowed to the mixed gas supply path 18 .

Furthermore, when the flow rate of TCS flowing into the first gas branch path 13b reaches 75% of the upper measurement limit Hm of the mass flow meter 19b, the third on-off valve 33 is opened in response to the voltage signal Sb, so that TCS It also flows into the third-stage first gas branch path 13c.

When TCS flows through the first gas branch path 13c, the mass flow controller 21c measures the flow rate of TCS and sends a voltage signal Sc. When the mass flow meter 19c receives the voltage signal Sc, the mass flow meter 19c causes the H2 at a flow rate corresponding to the voltage signal Sc to flow from the H2 supply unit 14 to the _second gas branch path 15c, so that _TCS and H2 join. The gas is also mixed in the portion 17c and flowed to the mixed gas supply path 18 .

Further, in a state in which the second on-off valve 32 and the third on-off valve 33 are opened by the supply of TCS, the flow rate of TCS distributed to the first gas branch path 13c and flowing into the first gas branch path 13c is 25% of the upper measurement limit Hm of the mass flow meter 19c. %, the third on-off valve 33 is closed in response to the voltage signal Sc, so that TCS does not flow into the first gas branch path 13c.

Furthermore, when the flow rate of TCS distributed to the first gas branch path 13b and flowing into it drops to 20% of the upper measurement limit Hm of the mass flow meter 19b, the second on-off valve 32 is closed in response to the voltage signal Sb. Therefore, TCS does not flow into the first gas branch path 13b.

FIG. 4 is a graph showing the transition of the gas flow rate flowing into each of the first gas branch paths 13a, 13b, and 13c as the flow rate of TCS increases in the multistage mixed gas supply device 30 of FIG. 4 is a graph showing the transition of the gas flow rate flowing into each of the first gas branch paths 13a, 13b, 13c as the flow rate of TCS decreases in the multi-stage mixed gas supply device 30 of FIG.

4 and 5, the measurement upper limit Hm of each mass flow meter 19a, 19b, 19c for measuring the flow rate of each first gas branch path 13a, 13b, 13c is set to 50 L/min.

As shown in FIG. 4, when the flow rate of TCS is increased from 0/min, only the first gas branch path 13a can flow in the range of 0 to 40 L/min, but 40 L/min (80% of Hm ), the second on-off valve 32 opens, allowing TCS to flow into the first gas branch path 13b as well. The flow rate of path 13b drops to 20 L/min.

When the flow rate of TCS is further increased and the flow rate of TCS in the first gas branch path 13a and the first gas branch path 13b exceeds 37.5 L/min (75% of Hm), the third on-off valve 33 opens. TCS can also flow into the first gas branch path 13c, and the flow rate of TCS is divided among the three paths. down to min.

By further increasing the flow rates, the flow rates of the first gas branch paths 13a, 13b, and 13c each reach 50 L/min, so the total flow rate of TCS can be increased to 150 L/min with high accuracy.

As shown in FIG. 5, when the flow rate of TCS is decreased from 150 L/min, inflow is possible in all of the first gas branch paths 13a, 13b, and 13c in the range of 150 to 40 L/min, but the total flow rate is When it falls below 37.5 L/min, that is, 12.5 L/min (25% of Hm) in each path, the third on-off valve 33 closes in the first gas branch path 13c, so TCS becomes unable to flow in, the flow rate of TCS is divided by two paths, and the flow rate of the first gas branch path 13a and the flow rate of the first gas branch path 13b rise to 18.75 L/min.

Furthermore, when the flow rate of TCS is decreased, and the total flow rate of TCS in the first gas branch passage 13a and the first gas branch passage 13b is 20 L/min, that is, 10 L/min ((20% of Hm) in each route, Since the second on-off valve 32 is closed in the first branched gas path 13b, only the first branched gas path 13a can flow, and the flow rate of the first branched gas path 13a increases to 20 L/min.

By further reducing the flow rate, the flow rate of the first gas branch path 13a reaches 5 L/min, so it is possible to accurately reduce the flow rate of the TCS to the lower measurement limit Lm.

As described above, according to the multi-stage mixed gas supply device 30 of the present invention, the paths for mixing TCS and H ₂ are branched and provided in multiple stages, and the paths through which TCS flows are sequentially opened as the flow rate of TCS increases. By doing so, it is possible to flow TCS with a flow rate that is the sum of the measurement upper limit values Hm of the mass flow meters 19a, 19b, and 19c at maximum, so that a large flow rate of mixed gas that cannot be handled by a single path can be supplied.

In addition, the first gas branch passages 13b and 13c in the second and subsequent stages are opened when the flow rate of the TCS in the preceding stage exceeds a predetermined range, and are closed when the flow rate falls below the predetermined range. , 13b, and 13c can be prevented, so that the flow rate of TCS can be accurately mixed with H2 within the range from the value obtained by multiplying the upper measurement limit Hm by the number of stages to the lower measurement limit Lm. can be done.

Furthermore, by conducting a concentration test to check whether mixing is performed correctly at each stage, it becomes easy to detect failures and abnormalities.

In addition, in the multi-stage mixed gas supply apparatus of this embodiment, each of the first branched path and the second branched path is provided in three stages. Four or more stages may be provided according to the required amount of the mixed gas at the facility.

For example, when the first branched path and the second branched path are provided in eight stages, the gas flow rate flowing into each first gas branched path accompanying the increase or decrease of the TCS flow rate transitions as shown in FIGS. Therefore, the flow rate of the first raw material gas can be accurately mixed with the second raw material gas within a range from the value obtained by multiplying the upper limit of measurement of the mass flow meter by the number of stages to the lower limit of measurement.

Here, in the second embodiment, the threshold for opening is gradually narrowed from 80% to 75%, and the threshold for closing is gradually narrowed from 25% to 20%. In the case of , the self-control width of the equipment provided in each first branch path is set in the range of 80% to 40%.

As described above, the dead band can be appropriately set depending on the full scale and the number of stages of the mass flow meter and the mass flow controller, and the component/ratio of the mixed gas to be supplied.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention. For example, in the present embodiment, the raw material gas is supplied from two of the first gas supply route and the second gas supply route. The raw material gas may be supplied from the supply route described above.

For example, when a laser gas containing 89% carbon dioxide (CO ₂ ), 10% helium (He), and 1% nitrogen (N ₂ ) is supplied at 20 L/min, the upper measurement limit for carbon dioxide is 17.8 L/min. value (full scale), and based on the signal, nitrogen is supplied to 0.2 L / min through a mass flow meter with an adjustment upper limit (full scale) of helium of 2 L / min. Continuous supply is possible by supplying via a mass flow meter with an adjustable upper limit (full scale).

A laser gas containing a mixture of fluorine (F2), krypton (Kr), neon (Ne), etc., can also be applied in the same manner. It is suitable when mixing and supplying.

Furthermore, when the raw material gas is supplied from three or more supply routes, the same kind of raw material gas may be supplied from two or more routes. By increasing the number of linked mass flow meters and mass flow controllers in this way, it is possible to reduce flow rate errors due to devices.

In addition, in the first embodiment, a cutoff valve is provided so that the gas supply can be cut off when the flow rate deviates from the measurement upper limit Hm and the measurement lower limit Lm of the mass flow meter. If it deviates from Lm, as shown in FIG. 8, the mixed gas may flow through a vent path 41 provided in the mixed gas supply path 18 . It is possible to avoid supplying to the consumption equipment 16 when the mixing ratio of the source gas is not guaranteed. An on-off valve may be provided in the vent path, and when the measurement lower limit value of the mass flow meter 19 is exceeded, the on-off valve may be opened to allow all the mixed gas to flow through the vent path 41. However, as shown in FIG. A mass flow controller 42 may be provided in the path 41 . This allows the mass flow controller 42 to receive the voltage signal S that is below the measurement lower limit value Lm and control the flow rate flowing through the vent path. However, if the pipe length is long, a difference in fluctuation occurs, making control difficult. It is preferable to adopt a value that can maintain a flow rate slightly higher than the measurement lower limit Lm of the mass flow meter 19 for the control flow rate to the vent. It is also possible to use both the shut-off valve mechanism of the first embodiment and the vent path mechanism of the present embodiment.

When the mixing ratio of the raw material gas is changed, the combination may be appropriately changed to a mass flow meter and a mass flow controller having a full scale that provides a predetermined ratio.

DESCRIPTION OF SYMBOLS 11... mixed gas supply apparatus, 12... TCS supply part, 13... 1st gas supply path, 13a, 13b, 13c... 1st gas branch path, 14... H2 supply part, 15... 2nd gas supply path, 15a, 15b , 15c... second gas branch path, 16... consumption facility, 17 (17a, 17b, 17c)... confluence section, 18... mixed gas supply path, 19 (19a, 19b, 19c)... mass flow meter, 20... first cutoff Valves 21 (21a, 21b, 21c) Mass flow controller 22 Second shut-off valve 23 Constant temperature bath 30 Mixed gas supply device 31 First on-off valve 32 Second on-off valve 33 Second 3 on-off valve, 41... Vent path, 42... Mass flow controller

Claims (2)

A mixed gas supply device for supplying a plurality of raw material gases mixed at a predetermined ratio,
a plurality of source gas supply paths;
a gas confluence unit for merging a plurality of raw material gases supplied from each raw material gas supply path to form a mixed gas;
a mixed gas supply path for supplying the mixed gas to a user,
one of the source gas supply paths is branched into a plurality of branches, each branched path is provided with a flow meter,
Other raw material gas supply routes are similarly branched into a plurality of branches, and each branch route is provided with a flow rate regulator,
The flow regulator is configured to receive a signal from the corresponding flow meter,
According to the detected flow rate, the flow rate measuring device transmits a signal indicating a flow rate ratio obtained by dividing by the upper limit of the flow rate that can be measured by the flow rate measuring device to the corresponding flow rate regulator,
When the flow rate regulator receives the signal, the flow rate regulator adjusts the flow rate of the raw material gas to a flow rate obtained by multiplying the upper limit of the adjustable flow rate of the flow rate regulator by the flow rate ratio,
When the flow rate detected by the flow rate measuring device provided in one of the branched paths of the source gas supply path exceeds a preset first flow rate, the source gas in the adjacent branched path starts to flow, and the first flow rate is reached. A mixed gas supply device characterized by interrupting the flow of the raw material gas in an adjacent branch path when the flow rate falls below a preset second flow rate that is less than the predetermined flow rate. A mixed gas supply method for supplying a plurality of raw material gases mixed at a predetermined ratio,
supplying a plurality of raw material gases to each raw material gas supply path;
one of the source gas supply paths is branched into a plurality of paths, each branched path is provided with a flow meter,
Other raw material gas supply routes are similarly branched into a plurality of branches, and each branch route is provided with a flow rate regulator,
one raw material gas is supplied through the flow meter, and an output signal based on the flow rate detected by the flow meter is used as an input signal to adjust the flow rate of the other raw material gas with a corresponding flow regulator;
When the flow rate detected by the flow rate measuring device provided in one branched path of the source gas supply path exceeds a preset first flow rate, the source gas in the adjacent branched path begins to flow,
When it falls below a preset second flow rate that is less than the first flow rate, the flow of the raw material gas in the adjacent branch path is cut off,
A method of supplying a mixed gas by combining a plurality of raw material gases to form a mixed gas.

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