WO2010122972A1

WO2010122972A1 - Liquid raw material vaporizer

Info

Publication number: WO2010122972A1
Application number: PCT/JP2010/056908
Authority: WO
Inventors: 孝之家城; 達也林
Original assignee: 株式会社堀場エステック
Priority date: 2009-04-21
Filing date: 2010-04-19
Publication date: 2010-10-28
Also published as: JP5702139B2; JPWO2010122972A1; CN102365388A; US20120042838A1

Abstract

A liquid raw material vaporizer which minimizes the bloating of bubbles by preventing recombination of bubbles and equalizes the temperature distribution of stored liquid raw material comprises a liquid raw material container (2), a first heater (3) mounted on the sidewall of the liquid raw material container (2) in order to heat the stored liquid raw material to a predetermined temperature, a second heater (4) provided at the central part in the liquid raw material container (2) in order to heat the stored liquid raw material to a predetermined temperature, a plurality of bubble generators (5) provided between the second heater (4) and the sidewall while being immersed in the stored liquid raw material in order to bubble the liquid raw material by discharging carrier gas into the liquid raw material, and a gas supply pipe (6) which supplies carrier gas to the bubble generators (5).

Description

Liquid raw material vaporizer

The present invention relates to a liquid raw material vaporizer that vaporizes a liquid raw material by a bubbling method using a carrier gas.

As this type of liquid source vaporizer, for example, as shown in Patent Document 1, a liquid source container for storing a liquid source and a carrier gas for bubbling the liquid source stored in the liquid source container with a carrier gas Some have an introduction pipe and a bubbling gas output pipe connected to the upper space (gas phase) of the liquid source container and for supplying the bubbling gas outside the liquid source container. And the front-end | tip part of a carrier gas introduction pipe | tube is immersed in the liquid raw material, The bubbling nozzle comprised by a some thin tube is connected to the front-end | tip part. In the process in which bubbles generated by the bubbling nozzle float up in the liquid raw material, the liquid raw material is vaporized in the bubbles, so that the gasified raw material is supplied to the outside together with the carrier gas. Further, a heater for heating the stored liquid material to a constant temperature is provided on the outer surface of the liquid material container, and the liquid material is configured to have a uniform temperature distribution.

However, there is a problem that bubbles generated by the bubbling nozzle adhere to the inner surface of the liquid raw material container or the components in the container, thereby recombining the bubbles and enlarging the bubbles. When the bubbles are enlarged as described above, the rate at which the liquid raw material is vaporized in the bubbles becomes small, the liquid raw material cannot be saturated in the bubbles, and the vaporization efficiency is lowered.

In addition, if the liquid source container is large, the bubble moving region generated by the bubbling nozzle is limited to a part, so the stirring effect of the liquid source due to the bubbles cannot be obtained, and the temperature distribution of the liquid source is reduced. There is a problem that it is difficult to keep it uniform. If the liquid source container is enlarged, it is difficult to heat the liquid source so that the temperature distribution of the liquid source is uniform only by providing a heater on the outer surface of the liquid source container. Here, a bubbling nozzle may be provided so that the bubbles hit the inner surface of the liquid source container, and the liquid source may be stirred. However, as described above, the bubbles adhere to the inner surface of the liquid source, and the bubbles recombine with each other. The problem will be that the bubbles will become enlarged.

Japanese Patent Application Laid-Open No. 06-267852

Therefore, the present invention has been made to solve the above problems all at once, and prevents recombination of bubbles to suppress the enlargement of bubbles and make the temperature distribution of the stored liquid raw material uniform. This is the main desired issue.

That is, the liquid raw material vaporizer according to the present invention includes a liquid raw material container in which the liquid raw material is stored, a first heater that is provided on at least the side wall of the liquid raw material container and heats the stored liquid raw material, A second heater provided inside the liquid source container for heating the stored liquid source, and immersed in the stored liquid source, and between the second heater and the side wall And a plurality of bubble generators for discharging and bubbling a carrier gas into the liquid raw material, and a gas supply pipe for supplying the carrier gas to the bubble generator.

If it is such, since the 1st heater and the 2nd heater are provided in the side wall and internal central part of a liquid source container, temperature distribution of the liquid source stored in the liquid source container is made uniform. Can be easily. Further, since the bubble generator is provided between the second heater and the inner surface of the side wall, it is possible to make it difficult for the air bubbles to come into contact with the second heater and the inner surface of the side wall. Can be prevented. Further, convection can be formed in the liquid source container, and the liquid source can be stirred. Furthermore, by providing a plurality of bubble generators, even if the liquid source container is large, the agitation effect of the liquid source can be sufficiently exerted by the bubbles generated by each bubble generator and stored. The temperature distribution of the liquid raw material can be made uniform easily.

By providing the plurality of bubble generators so that the bubbles generated by the plurality of bubble generators pass through the vicinity of the inner surface of the side wall of the liquid source container and the vicinity of the second heater, While being difficult to adhere to the inner surface of the side wall of the liquid source container and the second heater, the temperature distribution of the liquid source can be made more uniform by the bubbles generated by the bubble generator. The vicinity of the second heater is in the temperature gradient region generated between the second heater and the liquid raw material, and in the state where bubbles are generated, the influence of the bubbles attached to the second heater. Is a position that can be substantially ignored. In the vicinity of the inner surface of the side wall, in the temperature gradient region generated between the inner surface of the side wall and the liquid raw material, and in the state where bubbles are generated, the effect such as vaporization efficiency due to the adhesion of the bubbles to the inner surface of the side wall is substantial. The position is negligible.

Also, in order to make the temperature distribution of the liquid material even more uniform, it is desirable that the plurality of bubble generators be provided radially and equidistantly about the central axis of the liquid material container.

In order to make the temperature distribution of the liquid material uniform with high accuracy by making the bubbles generated from each bubble generator constant, the plurality of bubble generators have the same configuration, and the gas supply pipes are It is desirable to provide a constant flow device for supplying a carrier gas having a constant flow rate to the plurality of bubble generators.

According to the present invention configured as described above, the recombination of bubbles can be prevented to suppress the enlargement of bubbles, and the temperature of the liquid material stored in the liquid material container can be made uniform.

1 is an overall configuration diagram of a liquid raw material vaporizer according to an embodiment of the present invention. It is a schematic diagram which shows the arrangement | positioning aspect of the bubble generator of the embodiment. It is a figure which shows the temperature distribution of the liquid raw material between a side wall inner surface and a 2nd heater. It is sectional drawing which shows the pipe joint of the branch pipe and bubble generator of the embodiment. It is a figure which shows typically the liquid raw material vaporization apparatus which concerns on deformation | transformation embodiment.

DESCRIPTION OF SYMBOLS 100 ... Liquid raw material vaporizer 2 ... Liquid raw material container 3 ... 1st heater 4 ... 2nd heater 5 ... Bubble generator 6 ... Gas supply pipe | tube

Hereinafter, an embodiment of a liquid raw material vaporizer according to the present invention will be described with reference to the drawings.

The liquid source vaporization apparatus 100 according to the present embodiment is a device that vaporizes and supplies a liquid source serving as a film forming source to a film forming apparatus using a CVD method or the like by a bubbling method, as shown in FIG. A liquid raw material container 2 in which a liquid raw material such as tetraethoxysilane (TEOS) is stored, and provided on the side wall, upper wall, and lower wall of the liquid raw material container 2 for heating the stored liquid raw material to a predetermined temperature. A first heater 3, a second heater 4 provided at the center of the liquid source container 2 for heating the stored liquid source to a predetermined temperature, and immersed in the stored liquid source In addition, a plurality of bubble generators 5 provided between the second heater 4 and the side wall for discharging and bubbling a carrier gas into the liquid raw material, and a carrier such as nitrogen or argon in the bubble generator 5 Gas supply Comprising a gas supply pipe 6, the.

The liquid raw material container 2 is a stainless steel sealed container having a substantially rotating body shape. In an upper space (gas phase) formed in a state where the liquid raw material is stored, the vaporized liquid raw material after bubbling is used as a carrier gas. In addition, a gas outlet pipe 7 for supplying to a film forming apparatus (not shown) is connected. In addition, the figure in which the gas outlet pipe 7 is connected to the upper wall of the liquid raw material container 2 in FIG. 1 is shown.

The first heater 3 is provided in contact with or close to the entire outer surface of the side wall, upper wall, and lower wall of the liquid source container 2. Further, the second heater 4 is supported and provided on the upper wall so as to extend in the vertical direction at the inner central portion of the liquid source container 2. Note that the first heater 3 and the second heater 4 are heated to the same temperature (for example, 50 ° C.) by a control unit (not shown) in order to heat the liquid raw material to a predetermined temperature (for example, 50 ° C.). .

The bubble generator 5 discharges a carrier gas into the liquid raw material to form a large number of bubbles having a predetermined diameter, and the configuration of each bubble generator 5 is the same. The diameter of the bubble is such that the liquid source vaporizes and saturates in the bubble, and is about 1 mm, for example. Further, the flow rate of the carrier gas supplied to the bubble generator 5 is determined by a mass flow controller (MFC) 8 and a constant flow device, which will be described later.

The bubble generator 5 is provided in the vicinity of the bottom of the liquid raw material container 2. Specifically, the bubble generator 5 is positioned below the second heater 4 and radially outside the second heater 4. Is provided. More specifically, the bubble generator 5 is provided so that bubbles generated by the bubble generator 5 pass through the vicinity of the inner surface of the side wall of the liquid source container 2 and the vicinity of the second heater 4. In the present embodiment, the bubble generator 5 extends from the vicinity of the second heater 4 to the vicinity of the side wall of the container 2 between the second heater 4 and the side wall of the container 2 as shown in FIG. Is provided. That is, in the vertical projection, the second heater 4 and the side wall of the container 2 and the bubble generator 5 are provided so as not to overlap each other. Further, as shown in FIG. 2, the bubble generators 5 are provided radially and equidistantly about the central axis C of the liquid raw material container 2.

Here, as shown in FIG. 3, the vicinity of the second heater 4 is a temperature gradient region generated between the second heater 4 and the liquid material (“temperature gradient region on the second heater side” in FIG. 3). ) And in a state where bubbles are generated, the position is such that the influence of the bubbles attached to the second heater 4 can be substantially ignored. The vicinity of the inner surface of the side wall refers to the inner surface of the side wall in the temperature gradient region (the “temperature gradient region on the side wall side” in FIG. 3) generated between the inner surface of the side wall and the liquid raw material. This is a position where the effect of vaporization efficiency due to the adhesion of bubbles to the surface can be substantially ignored. The temperature gradient region is a region where the temperature of the liquid material changes as the liquid material moves away from the

heaters

3 and 4 in the horizontal direction at the liquid surface or a predetermined depth. FIG. 3 shows the temperature distribution of the liquid source at a predetermined depth X and its temperature gradient region.

The temperature gradient region generated between the second heater 4 and the liquid raw material is different when the operation of the second heater 4 starts (at the start of heating) and when the heating is stable, and is heated more than the temperature gradient region at the start of the operation. The stable temperature gradient region is narrower. Therefore, in order to bring the bubble generator 5 as close as possible to the second heater 4, it is preferable that the bubble generator 5 is provided in a temperature gradient region generated between the inner surface of the side wall and the liquid raw material at the time of stable heating. In addition, the temperature gradient region generated between the inner surface of the side wall and the liquid raw material is different at the start of operation of the first heater 3 (at the start of heating) and at the time of stable heating, and more stable than the temperature gradient region at the start of operation. The temperature gradient region at the time is narrower. Therefore, in order to bring the bubble generator 5 as close as possible to the inner surface of the side wall, it is preferable that the bubble generator 5 is provided in a temperature gradient region generated between the inner surface of the side wall and the liquid material at the time of stable heating.

The gas supply pipe 6 is provided by being inserted into the liquid source container 2 from the upper wall, and is provided along the second heater 4 in this embodiment. Specifically, the gas supply pipe 6 is provided by being inserted from the upper wall of the liquid source container 2 into the inside, and extends along the second heater 4 to the lower end of the lower end thereof, and the lower end of the main pipe 61. And a plurality of branch pipes 62 extending in the radial direction of the liquid raw material container 2.

The main pipe 61 is provided so that its pipe axis is substantially parallel to the central axis C of the liquid source container 2, and the branch pipe 62 is radially and radially in a direction substantially perpendicular to the pipe axis of the main pipe 61. Are branched at equal intervals. The bubble generator 5 is connected to the tip of the branch pipe 62. That is, the gas supply pipe 6 is configured to be branched on the lower side below the lower end of the second heater 4. The main pipe 61 is provided with a mass flow controller (MFC) 8 for controlling the flow rate of the carrier gas and a preheater 9 for preheating the carrier gas.

As described above, the pipe of only the main pipe 61 exists in the upper part of the bubble generator 5, so that the pipe structure of the upper part of the bubble generator 5 can be simplified, and the bubbles generated from the bubble generator 5 come into contact with the pipe. Can be suppressed as much as possible.

Further, as shown in FIG. 4, the branch pipe 62 and the bubble generator 5 are connected by a pipe joint 10 such as a VCR joint, for example. And the orifice as a constant flow device is comprised by making small the opening diameter of the cyclic | annular metal sealing material (gasket) 11 provided in the inside of this pipe joint 10. FIG. The pipe joints 10 of the respective branch passages 62 and the respective bubble generators 5 have the same configuration, and the sealing material 11 therein also has the same configuration. Thereby, it is comprised so that the supply flow rate of the carrier gas supplied to each bubble generator 5 may become the same.

<Effect of this embodiment>
According to the liquid raw material vaporization apparatus 100 according to the present embodiment configured as described above, since the first heater 3 and the second heater 4 are provided on the side wall and the inner central portion of the liquid raw material container 2, the liquid raw material container The temperature distribution of the liquid raw material stored in 2 can be made uniform easily. In addition, since the bubble generator 5 is provided between the second heater 4 and the inner surface of the side wall, it is possible to make it difficult for the bubbles to contact the second heater 4 and the inner surface of the side wall, and the bubbles adhere to them. Bubbles can be prevented from growing. Further, by providing a plurality of bubble generators 5, even if the liquid source container 2 is large, the stirring effect of the liquid source can be sufficiently exerted by the bubbles generated by each bubble generator 5, The temperature distribution of the stored liquid raw material can be made uniform easily.

<Other modified embodiments>
The present invention is not limited to the above embodiment.

For example, in the embodiment, the carrier gas supply pipe is composed of one main pipe and a plurality of branch pipes, but one carrier gas supply pipe is provided for each bubble generator without branching the carrier gas supply pipe. May be provided. Further, a plurality of bubble generators may be grouped, and a carrier gas supply pipe similar to that of the above embodiment may be provided for each group.

Further, the connection position of the carrier gas supply pipe is not limited to the upper wall of the liquid source container, and may be a side wall or a lower wall.

Furthermore, in the said embodiment, although the constant flow device provided in the branch pipe of a carrier gas supply pipe is comprised using the sealing material provided in a VCR joint inside, it is made to provide a constant flow device separately on a branch pipe. Also good.

In addition, as shown in FIG. 5, by supplying a plurality of bubble generators as a group, carrier

gas supply pipes

6A and 6B are provided for each group, and switching valves V are provided in the

supply pipes

6A and 6B. You may comprise so that the liquid raw material may be vaporized by switching the

pipes

6A and 6B. In this case, a pressure sensor P for measuring the pressure in each of the

supply pipes

6A and 6B is provided, and the bubble generator 5 is clogged when the pressure in one of the supply pipes used is increased to a predetermined value or more. Therefore, bubbles are generated by switching to the other supply pipe. FIG. 5 shows a configuration in which the carrier

gas supply pipes

6A and 6B merge on the upstream side and a pressure sensor P is provided at the junction to measure the pressure. In this case, when a problem such as clogging of a bubble generator provided in one carrier gas supply pipe occurs, switching to the other carrier gas supply pipe enables long-term operation.

The liquid material vaporization apparatus of the above embodiment is configured using a plurality of bubble generators. In addition, a single bubble generator having an annular shape (for example, an annular shape) is used to surround the second heater. It may be configured.

In addition, in the above-described embodiment, the four bubble generators are provided. However, the number of bubble generators can be appropriately changed depending on the configuration of the flow rate of the carrier gas or the size and shape of the liquid source container.

In addition, in the above embodiment, the bubble generators are provided radially at equal intervals, but the arrangement mode of the bubble generators can be changed as appropriate depending on the configuration in the liquid source container.

Further, even if the liquid raw material vaporizer of the embodiment does not have the second heater, the liquid raw material can be vaporized, but if the liquid raw material container is enlarged, the vaporization efficiency is lowered. On the other hand, if the liquid material container is small, the liquid material can be sufficiently vaporized only by the first heater. That is, if the liquid source container is small, the liquid source vaporizer is provided on at least the side wall of the liquid source container in which the liquid source is stored and the liquid source container, and heats the stored liquid source And a plurality of bubble generators for immersing in the stored liquid raw material, releasing a carrier gas into the liquid raw material and bubbling, and supplying the carrier gas to the bubble generator It is desirable that a plurality of bubble generators be provided so that bubbles generated by the plurality of bubble generators pass in the vicinity of the inner surface of the side wall of the liquid raw material container.

In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

According to the present invention, the recombination of bubbles can be prevented to suppress the enlargement of bubbles, and the temperature of the liquid raw material stored in the liquid raw material container can be made uniform.

Claims

A liquid source container in which the liquid source is stored;
A first heater provided on at least a side wall of the liquid source container for heating the stored liquid source;
A second heater provided in the liquid source container for heating the stored liquid source;
A plurality of bubble generators that are immersed in the stored liquid raw material and provided between the second heater and the side wall, for discharging a carrier gas into the liquid raw material and bubbling;
A liquid raw material vaporizer comprising: a gas supply pipe for supplying a carrier gas to the bubble generator.
2. The plurality of bubble generators are provided so that bubbles generated by the plurality of bubble generators pass through the vicinity of the inner surface of the side wall of the liquid source container and the vicinity of the second heater. Liquid raw material vaporizer.
The liquid raw material vaporizer according to claim 1, wherein the plurality of bubble generators are provided radially and equidistantly about a central axis of the liquid raw material container.
The liquid material according to claim 1, wherein the plurality of bubble generators have the same configuration, and the gas supply pipe includes a constant flow device for supplying a carrier gas having a constant flow rate to the plurality of bubble generators. Vaporizer.