JPH0142739B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Technical Field> The present invention relates to a bubbling device for sending raw material gas whose flow rate is precisely controlled to a reaction device in optical fiber or semiconductor manufacturing equipment.

<Prior art> Bubbling devices are widely used in optical fiber and semiconductor manufacturing equipment, which supply a carrier gas to a bubbler container holding a raw material liquid to bubble the raw material liquid, convert it into a mixed gas of the raw material gas and carrier gas, and send it to a reaction device through piping. It is used. In such a bubbling device, as a method for precisely controlling the flow rate of the raw material gas in the mixed gas, the flow rate of the carrier gas introduced into the bubbler container is precisely controlled, and the flow rate of the carrier gas introduced into the bubbler container is precisely controlled. It is known that a condenser maintained at a constant temperature is interposed, and the condenser converts the mixed gas into saturated vapor of the raw material gas at the temperature of the condenser. A block diagram of an example of such a conventional bubbling device is shown in FIG. According to the bubbling device shown in FIG. 1, a raw material liquid 2 is stored in an airtight bubbler container 1, and a heater 3 is attached to the outer peripheral surface of the bubbler container 1 to control the raw material liquid in the bubbler container 1 to a predetermined level. Keeps at temperature.
A pipe 4 having an open end is inserted into the bubbler container 1 into the liquid 2. A precision flow meter 5 is interposed in the pipe 4. As the precision flowmeter 5, a mass flowmeter is widely used to precisely measure the flow rate of the carrier gas flowing through the pipe 4 and supplied to the bubbler container 1. On the other hand, the raw material liquid 2 in the airtight bubbler container 1
A pipe 6 having a suction end P is led out to the upper space of
The pipe 6 is connected to the lower end Q of the winding tube 9 of the condenser 7. The condenser 7 is kept at a constant temperature by circulating water or the like. A pipe 8 leading to a reaction container (not shown) is connected to the upper end R of the winding tube 9. The piping 6 and the piping 8 are provided with heating means (not shown). In the apparatus shown in FIG. 1, the flow rate of the carrier gas is precisely controlled by a precision flowmeter 5, and the carrier gas is fed into the raw material liquid 2 of the bubbler container 1 through the piping 4. The carrier gas is produced by bubbling the raw material liquid 2 in the bubbler container 1.
The space above the raw material liquid 2 in the bubbler container 1 is filled with a mixed gas of carrier gas and raw material gas. When the flow rate of the carrier gas is large, the mixed gas usually does not become saturated vapor of the raw material gas at the temperature of the bubbler container. The liquid temperature is kept higher than the capacitor temperature by the heater 3. Usually, the difference between the raw material liquid temperature and the capacitor temperature is 5°C to 10°C. The mixed gas in the upper part of the bubbler container is led to the reaction container via piping 6, condenser 7, and piping 8. The condenser 7 is kept at a constant temperature by circulating hot water, and the mixed gas that has passed through the condenser 7 is cooled to the condenser temperature and becomes saturated steam at the condenser temperature. In this process, excess raw material gas condenses in the winding tube 9 inside the condenser,
The condensed raw material liquid is transferred from the winding pipe 9 to the pipe 6 by gravity.
, and then return to bubbler container 1. Piping 6 and Piping 8
is kept above the condenser temperature to prevent the raw material gas of the mixed gas from condensing in these pipes. In this way, by precisely controlling the flow rate of the carrier gas and making the mixed gas a saturated vapor at the condenser temperature,
By keeping the partial pressure of the raw material gas constant, a mixed gas with a precisely controlled flow rate of the raw material gas can be sent to the reaction vessel. However, in such a bubbling device, as the mixed gas flow rate increases, the raw material liquid condenses in the condenser and falls into the bubbler container, and the mixed gas flow toward the reaction container is in the opposite direction. The flow within the pipe 9 is obstructed, and the water cannot return to the bubbler vessel 1 through the pipe 6, and instead remains in the condenser tube 9, or flows from the condenser 7 toward the reaction vessel. If this condition is left untreated, the accumulated condensate will increase the resistance in the pipe to the mixed gas flow in the condenser 7, making it impossible to stably send the raw material gas to the reaction vessel, or causing backflow inside the condenser tube 9. The raw material liquid reaches the pipe 8, is re-vaporized in the high-temperature pipe 8, and is sent to the reaction vessel, causing the condenser 7 to lose its function of controlling the flow rate of the raw material gas, making it impossible to achieve the purpose. It disappears. The simplest means to solve this problem is to increase the inner diameter of the condenser tube 9. However, in order to increase the inner diameter of the winding tube 9 of the capacitor, there is a drawback that the capacitor must be made larger. Another method is to connect multiple condenser winding tubes in parallel to reduce the mixed gas flow per winding tube, but in this case it is difficult to divide the mixed gas flow uniformly to all the winding tubes. In addition to this, there is a disadvantage that the overall size of the capacitor becomes large.

<Object of the invention> The present invention has been made in view of the drawbacks of the prior art, and an object of the present invention is to provide a bubbling device that can stably send a large flow rate of raw material gas to a reaction device. It is.

<Specific means for solving the problem> The configuration of the bubbling device according to the first invention that achieves the above object includes bubbling a liquid raw material kept in a bubbler container with a carrier gas to create a mixed gas of the carrier gas and the raw material gas, In the bubbling device, the mixed gas is passed through a winding tube of a condenser kept at a constant temperature, and the mixed gas is introduced into the reactor as saturated vapor of the raw material gas at the above-mentioned temperature of the condenser, from the bubbler container to the reactor. A pipe for supplying the mixed gas is led out from the space above the liquid in the bubbler container, passes from the upper end of the winding tube of the condenser to the lower end, and further connects an upward branch to one of the two branch pipes provided at the lower end. The other downward branch of the branch pipe is opened into the liquid in the container.

Further, the configuration of the bubbling device of the second invention is such that a raw material liquid kept in a bubbler container is bubbled with a carrier gas to create a mixed gas of the carrier gas and the raw material gas, and the mixed gas is wrapped around a condenser kept at a constant temperature. In the bubbling device, the mixed gas is passed through a pipe and guided to the reaction device as saturated vapor of the raw material gas at the temperature of the condenser, and the pipe for supplying the mixed gas from the bubbler container to the reaction device is configured to supply the liquid in the bubbler container. It is led out from the upper space, passes from the upper end of the winding tube of the condenser to the lower end, passes through an upward branch of one of the two branch pipes provided at the lower end, is led to the reaction apparatus, and is led to the lower part of the other branch pipe. The opposite branch is led to a liquid reservoir,
The liquid reservoir is characterized in that a pipe that is open to the bubbler container is led out through an on-off valve to the lower end of the liquid reservoir.

<Example> An example of a bubbling device according to the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of a bubbling device according to the present invention. As shown in FIG. 2, an airtight bubbler container 1 contains a raw material liquid 2 for manufacturing optical fibers and semiconductors, and a heater 3 is installed on the outer peripheral surface of the container. The heater 3 is for maintaining the raw material liquid 2 at a predetermined temperature. A piping 4 for supplying carrier gas is inserted into the raw material liquid 2 in the bubbler container 1 . A precision flow meter 5 is interposed in the middle of the pipe 4 to measure the flow rate of the carrier gas being fed. As the precision flowmeter 5, a mass flowmeter is widely used. On the other hand, a pipe 6 having an open end P is led out into the space above the raw material liquid 2 in the bubbler container 1 . The space above the raw material liquid 2 in the bubbler container 1 is filled with a mixed gas of the carrier gas fed into the bubbler container 1 and the raw material gas obtained by vaporizing the raw material liquid. supplied to A two-branch pipe is provided at the lower end Q of the winding pipe 9,
One upward branch communicates with a reaction vessel (not shown) via piping 11 and piping 8. The other downward branch of the two-branch pipe has an open end connected to a pipe 10 inserted into the raw material liquid 2 of the bubbler container.

Note that the condenser 7 is kept at a constant temperature by circulating hot water. Condenser 7 by pipe 6
The mixed gas supplied to the upper end R of the winding tube 9 of the condenser 7 is cooled to a predetermined temperature within the winding tube 9 of the condenser 7, and the raw material gas becomes saturated vapor at that temperature. In this process, excess raw material gas condenses inside the winding tube 9, and the condensed raw material liquid falls through the winding tube 9 due to gravity, leading to branch pipes,
It returns to the raw material liquid 2 via the pipe 10. Further, the mixed gas of the saturated steam raw material gas and the carrier gas is sent to the reaction vessel via the branch pipe at the lower end Q of the winding tube 9, the pipe 11, and the pipe 8. Although the illustrated pipe 11 is a straight pipe, it may be a wound pipe. The piping 6 and the piping 8 are maintained at a temperature higher than that required to prevent the raw material gas in the mixed gas from condensing within the pipes.

Using the bubbling device according to the present invention shown in FIG. 2, a mixed gas whose flow rate of raw material gas is precisely controlled is sent to a reaction vessel by the following method. The flow rate of the carrier gas is precisely controlled using a precision flowmeter 5, and the carrier gas is passed through piping 4 to bubbler container 1.
into the raw material liquid 2 inside. By bubbling the raw material liquid with the carrier gas in the bubbler container 1, a mixed gas of the carrier gas and the raw material gas is formed in the upper part of the bubbler container 1. When the flow rate of the carrier gas is large, the mixed gas usually does not become saturated vapor of the raw material gas at the temperature of the bubbler container. The liquid temperature of the raw material liquid 2 is kept higher than the condenser temperature by the heater 3 in order to make the mixed gas into saturated vapor of the raw material gas at the condenser temperature at the condenser outlet. Normally the temperature difference between raw material liquid temperature and capacitor temperature is 5℃~10℃
It is. In the condenser 7, the mixed gas rises along the piping 6 to the upper end R of the winding tube 9 at the top of the condenser, then descends along the downward winding tube 9, and is transferred to one side by a two-branch pipe at the lower end Q of the winding tube. The upward branch enters the pipe 11, passes through the condenser, is communicated with the pipe 8 at the condenser outlet S, and is fed to the reaction vessel. The condenser 7 is kept at a constant temperature with circulating hot water, and the mixed gas that has passed through the condenser 7 from top to bottom is cooled to the condenser temperature, and the raw material gas in the mixed gas becomes saturated vapor at the condenser temperature. In this process, excess raw material gas is condensed in the piping inside the condenser, and the condensed raw material liquid flows down along the piping and returns to the bubbler container 1. The raw material liquid condensed in the pipe 6 from the inlet of the condenser 7 of the pipe 6 to the upper end R of the condenser winding tube 9 flows down through the vertical pipe 6 in a direction opposite to the mixed gas and returns to the bubbler container 1 . Note that although the raw material liquid flowing down inside the pipe 6 flows in the opposite direction to the mixed gas, the pipe 6 is a straight pipe and flows downward without being obstructed. From the upper end R to the lower end Q of the capacitor winding tube 9
The raw material liquid condensed between 1 and 2 flows down along the winding pipe 9 with a gentle slope, but since the flow direction of the mixed gas flow and the raw material liquid are the same, the flow of the raw material liquid is obstructed by the mixed gas flow. Rather, it is accelerated and flows along the winding tube 9 to the lower end. It returns to the bubbler container 1 through a branch pipe at the lower end Q of the winding tube 9 and through a piping 10. At this time, the open end T of the pipe 10 is connected to the raw material liquid 2.
If not, the mixed gas will enter the pipe 11 in the condenser through the pipe 10 and escape to the pipe 8, making it impossible to obtain saturated vapor of the source gas at the condenser temperature. . The mixed gas that has passed through the branch pipe passes through a pipe 11 provided in the condenser 7 and is sent to the reaction vessel via a pipe 8 connected at the outlet S of the condenser. When the mixed gas passes through the pipe 11, the raw material gas is sufficiently cooled by the winding tube of the condenser, so there is little raw material liquid condensed in the pipe 11, and even if it is condensed, the pipe 11 is a straight pipe. Even if it moves against the mixed gas, the gravity acting on the flowing raw material liquid does not pose a big problem. Both the pipe 6 introduced into the condenser 7 and the pipe 8 led out from the condenser 7 are maintained at a temperature higher than the required temperature so that the raw material gas does not condense within the pipes.

According to the bubbling device of the present invention, the flow rate of the carrier gas is precisely controlled by the carrier gas flowmeter, and the raw material gas is made into saturated vapor by the condenser 7, thereby stabilizing the raw material gas at a predetermined concentration at a large flow rate. This makes it possible to feed the reactor to the reaction vessel.

When using the device shown in Figure 2, in order to prevent mixed gas from entering the condenser from the pipe 10,
The open end T of the pipe 10 is open into the raw material liquid. Therefore, the pressure difference between the cavity of the bubbler container 1 and the branch pipe part Q at the lower end of the winding tube of the condenser 7 should not become so large that the raw material liquid rises in the pipe 10 due to this pressure difference and reaches the branch pipe part Q. It is necessary to Normally, the pressure difference during this period is about 10mmH ₂ O,
The rise in the raw material liquid level within the pipe 10 is about 1 cm, so it is not a problem. However, another embodiment of the bubbling device according to the present invention, which further solves this problem, is shown in FIG.

Comparing the embodiment shown in FIG. 3 with the embodiment shown in FIG. 2, one upward branch of the branch pipe provided at the lower end Q of the condenser 7 is connected to the pipe 11, and the other downward branch is connected to the pipe 11. Via piping 10, liquid reservoir 1
2. Through the on-off valve 13 and piping 10, the piping 10
The open end T of is open to the bubbler container 1 (not necessarily in the liquid). The one in FIG. 3 differs from the one in FIG. 2 only in the piping 10, and the other parts are the same. Therefore, in the embodiment shown in FIG.
The raw material liquid condensed in step 1 flows down inside the winding pipe 9 and straight pipe 11, respectively, and instead of being returned to the bubbler container 1 via the branch pipe and through the pipe 10, it flows into the pipe 1.
The liquid is collected in a liquid reservoir 12 provided halfway through the process. When the recovered raw material liquid is not being supplied to the bubbler container, the on-off valve 13 is opened to return the raw material liquid in the liquid reservoir 12 to the bubbler container.

In the case shown in FIG. 3, there is no possibility that the mixed gas or the raw material liquid flows back toward the condenser from the bubbler container 1 through the pipe 10 for recovering the raw material liquid.

FIG. 4 is a schematic diagram of another embodiment of the bubbling device according to the present invention. In the embodiment shown in FIG. 2, when the flow rate of the mixed gas flowing through the winding tube 9 in the condenser is high, the lower end Q of the winding tube 9 in the condenser
The mist of the mixed gas and the condensate are not completely separated in the branch pipes, and the condensate may mix with the mixed gas in the pipes 11 and 8. What is shown in FIG. 4 is a bubbling device that can completely separate the mixed gas and condensate even in such a case. In the case shown in FIG. 4, a bifurcated pipe at the lower end Q of the winding tube of the condenser 7 serves as a gas reservoir 14, a pipe 11 is connected to the pipe 8 from the gas reservoir 14, and another pipe 10 is connected from the gas reservoir 14 to the pipe 8. A baffle plate 15 is provided in the gas reservoir 14 which is configured to branch and return the condensed raw material liquid to the bubbler container 1. In the apparatus shown in FIG. 4, when the mixed gas and condensate flowing at a high flow rate flow into the gas reservoir at the lower end of the winding tube 9, the flow rate decreases and the condensate and the mixed gas are separated. When the condensate collides with the cutting board, the separation of the mixed gas and condensate becomes even better. The raw material liquid separated by the cutting board is transferred to pipe 10.
The mixed gas returns to the bubbler container through the tube 1.
1 and 8 to the reaction vessel. Of course, the gas reservoir 1 having the jamb plate 15 shown in FIG.
4 can constitute the two-branch pipe shown in FIG.

The piping 6 in the bubbling device of the present invention shown in FIGS. 2 to 4 runs straight through the condenser 7 and is connected to the winding tube at the upper end R of the winding tube 9, so that the mixed gas flows through the pipe 6. When passing through the straight pipe section in the condenser 7, the raw material gas condenses and flows down along the pipe 6, but if you want to avoid the condensate flowing backwards in this section when flowing a large flow of mixed gas, The heated piping 6 may be piped outside the condenser to the upper end of the condenser 7 and introduced into the condenser at the upper end.

Experimental examples showing the effectiveness of the bubbling device according to the present invention are shown below. Silicon tetrachloride SiCl ₄ is kept as a raw material liquid 2 in a bubbler container 1, and the temperature of the raw material liquid is maintained at 50°C by a heater 3.
A comparative experiment was conducted between a conventional condenser kept at 44°C and a condenser 7 of the present invention, in which a carrier gas of He gas, which was precisely measured with a flowmeter, was supplied to the gas mixture, and a mixed gas was prepared. In the case of conventional bubbling equipment, the inner diameter of the condenser tube is 10 mm.
However, when He gas was continued to flow into the condenser 7 for 13 minutes at a He flow rate of 400 c.c./min, the raw material liquid stagnation occurred in the condenser winding tube 9, and stable raw material gas did not flow into the reaction vessel. The supply was no longer available. In the case of the present invention shown in Fig. 2, the inner diameter of the condenser tube is
Although the diameter of the condenser was 7.5 mm, the raw material liquid did not stagnate in the condenser even when He gas was continuously flowed for 1 hour at a He gas flow rate of 800 c.c./min.

<Effects of the Invention> According to the bubbling device according to the present invention, a mixed gas is fed to the winding tube of the condenser from the upper end to the lower end, and the raw material liquid condensed in the condenser is passed through the branch provided at the lower end of the winding tube. Because it can be collected through a pipe, the flow direction of the raw material liquid condensed in the condenser matches the feeding direction of the mixed gas, making it possible to stably send a large amount of raw material gas with a constant raw material concentration to the reactor. I made it.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional bubbling device, Figure 2
3 is a block diagram of one embodiment of the bubbling device according to the present invention, FIG. 3 is a block diagram of another embodiment of the present invention, and FIG. 4 is a block diagram of still another embodiment of the present invention. In the drawing, 1 is a bubbler container, 2 is a raw material liquid, 3 is a heater, 4, 6, 8, 10, 11 are piping, 5 is a gas flow meter, 7 is a condenser, 9 is a winding tube, 12 is a liquid reservoir, 13 14 is an on-off valve, 14 is a gas reservoir, and 15 is a block board.

Claims (1)

[Claims] 1. A liquid raw material kept in a bubbler container is bubbled with carrier gas to create a mixed gas of carrier gas and raw material gas, and the mixed gas is passed through a condenser tube kept at a constant temperature. , in the bubbling device for introducing the mixed gas to the reaction device as saturated vapor of the raw material gas at the above-mentioned temperature of the condenser, a pipe for supplying the mixed gas from the bubbler container to the reaction device is led out from the space above the liquid in the bubbler container. from the upper end of the winding tube of the capacitor to the lower end, and further provided at the lower end.
A bubbling device characterized in that the bubbling device is led to the reaction device through one of the branch pipes, and the other downward branch of the branch pipe is open to the liquid in the bubbler container. 2. The bubbling device according to claim 1, wherein the two-branch pipe is constituted by a gas reservoir having a wall plate. 3 Bubble the raw material liquid held in the bubbler container with carrier gas to create a mixed gas of carrier gas and raw material gas, and pass the mixed gas through the winding tube of a condenser kept at a constant temperature to convert the mixed gas into the above-mentioned In a bubbling device that introduces the raw material gas as saturated vapor at the temperature of the condenser to the reaction device, a pipe for supplying the mixed gas from the bubbler container to the reaction device is led out from the liquid upper space of the bubbler container, and is connected to the condenser tube. From the upper end to the lower end, the liquid is led to the reactor via one upward branch of the two-branch pipe provided at the lower end, and the other downward branch of the branch pipe is led to a liquid reservoir. A bubbling device characterized in that a pipe that is open to the bubbler container is led out from the lower end of the reservoir via an on-off valve. 4. The bubbling device according to claim 3, wherein the two-branch pipe is constituted by a gas reservoir having a wall plate.