JPH10147870A - Vaporizer for liquid raw material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vaporizer capable of efficiently and continuously supplying a vaporized raw material that has a stable composition and a stable concn. to a treatment chamber even at the time of using any of various liquid raw materials. SOLUTION: This vaporizer is used for a treatment process that involves vaporizing a liquid raw material 2 and introducing the vaporized raw material into a treatment chamber 10, to subject an object to be treated 11 to prescribed treatment in the treatment chamber 10. At this time, the vaporizer is provided with: a raw material vessel 1 for receiving the liquid raw material 2; a raw material transfer means 3 and a raw material transfer passage 4, both of which are used for transferring the liquid raw material 2; and a vaporization mechanism 8 placed in the raw material transfer passage 4; wherein the vaporization mechanism 8 is a high temp. heat exchanger that has a small diameter pipe 25 for passing the liquid raw material 2 through the mechanism 8 and a heat source for heating the small diameter pipe 25 from its outside and also, on the upstream side of the vaporization mechanism 8 in the raw material transfer passage 4, a vaporization prevention mechanism 7 for preventing the liquid raw material 2 flowing in the raw material transfer passage 4 up to the vaporization mechanism 8 from being influenced by the heat from the mechanism 8, is placed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for vaporizing a liquid source, and more particularly to a vaporizer for vaporizing a liquid source used for chemical vapor deposition in a good and continuous manner and introducing it into a processing chamber of a thin film deposition apparatus. About.

[0002]

2. Description of the Related Art In an integrated circuit manufacturing process using a semiconductor, a raw material is vaporized and transported onto a surface of an object to be processed in a processing chamber.
2. Description of the Related Art Chemical vapor deposition (hereinafter, referred to as CVD) in which a predetermined thin film is deposited using a chemical reaction is widely used.

[0003] Among the raw materials used in the CVD method, those usually stored in a raw material container in a liquid state, appropriately vaporized at the time of use, and introduced into a processing chamber and used, for example, organic silicon-based TEOS (Tetraethoxy ortho silicat
e, Si (OC ₂ H ₅ ) ₄ ). FIG. 4 is a schematic diagram showing an example of a method of vaporizing TEOS. This is a method by bubbling which is generally performed. As shown in the figure, the liquid raw material 2 is put in an evaporation container 41, and the carrier gas 20 is kept on a liquid surface or in a liquid while maintaining a constant temperature. Then, a certain amount of the liquid raw material 2 corresponding to the vapor pressure at that temperature is evaporated and transported to the processing chamber 10. At this time, the supply amount of the raw material gas is determined by the evaporation temperature and the flow rate of the carrier gas.

[0004] As a raw material, there is a liquid raw material in which an organic metal compound is dissolved in an organic solvent. Since this kind of liquid raw material is composed of a solvent having a low boiling point and an organic metal compound having a high boiling point, the above-described vaporization method shown in FIG. 4 cannot be used. In this method of vaporizing the raw material, the liquid raw material is transported from a raw material container containing the liquid raw material to a vaporizer provided separately from the raw material container by a pump or a pressurized inert gas, where the liquid raw material is heated and vaporized. And transporting the vaporized raw material to a processing chamber.

FIG. 5 is a schematic view showing an example of a conventional method for vaporizing a liquid raw material. In FIG. 5, a liquid raw material 2 stored in a raw material container 1 is sent to a raw material transport pipe 4 by a raw material pump 3. After being weighed and flow-controlled by the flow controller 5, it is sent to the nozzle 43. The liquid raw material 2 is atomized by a nozzle 43 and is heated by a heater 9 by a high-temperature heat exchanger 8.
And is sent onto the surface of the processing object 11 in the processing chamber 10. There is also a method of atomizing a liquid raw material using an ultrasonic transducer without using a nozzle. Furthermore, entraining the atomized raw material with a hot carrier gas is also widely and commonly used. FIG. 6 shows an example of another conventional vaporization method. In this method, the liquid raw material is vaporized by passing through a heated porous body (or granular aggregate) 44.

[0006]

However, each of the conventional vaporizers described above was insufficient to efficiently and continuously supply vaporized raw materials to the processing chamber with a stable composition and concentration.

In the conventional vaporization method shown in FIG.
The liquid raw material in the evaporation container was heated by a thermostat, and the vaporized raw material was transported by the carrier gas. In this method, it is difficult to keep the pressure in the evaporation container and the temperature of the liquid raw material constant, and it is difficult to control the raw material concentration in the carrier gas to be constant. Furthermore, raw materials of mixtures having different boiling points cannot be handled at once.

In the conventional vaporization method shown in FIG.
The liquid raw material is atomized by a nozzle, and the heater is heated to vaporize the atomized raw material in the high-temperature heat exchanger. However, when the liquid raw material is a liquid raw material obtained by dissolving an organometallic compound in an organic solvent, the organic compound or its alteration precipitates near the nozzle and on the inner wall of the high-temperature heat exchanger, and stably and continuously converts a certain vaporized raw material. It was difficult to supply to the processing room.

In the conventional vaporization method shown in FIG. 6, even when the liquid raw material is a liquid raw material in which an organic metal compound is dissolved in an organic solvent, if the temperature control of the porous body is insufficient, the organic metal compound or its modified product Was deposited on the porous body, and the passage was closed.

[0010] It is an object of the present invention to provide a vaporizer for efficiently and continuously supplying a vaporized raw material to a processing chamber with a stable composition and concentration for various liquid raw materials.

[0011]

Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and an invention according to claim 1 is a method for performing a predetermined process on a workpiece in a processing chamber. In a liquid material vaporizer for vaporizing the raw material and introducing the raw material into the processing chamber, a raw material container for storing the liquid raw material,
A source transporting means and a source transport path for transporting the liquid source; and a vaporization mechanism disposed in the source transport path, wherein the vaporization mechanism heats the thin tube through which the liquid source flows and the thin tube from outside. High-temperature heat exchanger having a heat source to perform, upstream of the vaporization mechanism of the raw material transport path,
An apparatus for vaporizing a liquid raw material, wherein a vaporization preventing mechanism for preventing the heat of the vaporizing mechanism from affecting the liquid raw material in the raw material transporting path leading to the vaporizing mechanism is provided. is there.

In such a configuration, a thin tube is used so that heat exchange per unit flow rate is easy, so that the liquid material inside is heated at once and uniformly, so that a temperature region in which the material is decomposed or deteriorated. The vaporization process is performed instantaneously and a stable vaporization process is performed. By appropriately setting the length and the diameter, the conductance can be changed and the passage time of the raw material necessary for vaporization can be appropriately set. By providing the vaporization preventing mechanism, it is possible to prevent a premature alteration of the raw material due to the thermal influence of the vaporizing mechanism and a solute precipitation due to partial vaporization of the solvent, and to provide a stable and high quality vaporized raw material. Further, the structure of the thin tube itself is simple and hard to cause clogging, etc., the manufacturing cost is low, the replacement at the time of maintenance is easy, and the attachment of the vaporization preventing mechanism is easy.

According to a second aspect of the present invention, the high-temperature heat exchanger has a double cylindrical structure composed of the thin tube and the outer tube, and a heat medium supplied from a thermostat is flowed into the outer tube. 2. The liquid raw material vaporizer according to claim 1, wherein the heat source is a high-temperature heat exchanger that keeps the surface of the thin tube at a predetermined temperature. Thereby, there is an advantage that it is easy to always maintain a constant temperature and stable vaporization can be performed.

According to a third aspect of the present invention, the heat source for heating the thin tubes of the high-temperature heat exchanger is an electric heater, and the output of the electric heater is variable so that the temperature of the thin tubes is detected to detect the temperature of the thin tubes. 2. The liquid raw material vaporizer according to claim 1, wherein the output is controlled. Thereby, the response of the temperature control is high, and efficient vaporization can be performed.

According to a fourth aspect of the present invention, the inner diameter of the thin tube is 3 mm or less.
3. A vaporizer for a liquid raw material according to (1). By setting the diameter of the thin tube to 3 mm or less, the liquid raw material can be heated uniformly and quickly, and good vaporization can be stably performed.

The invention according to claim 5 is the liquid material vaporizer according to claim 1, wherein the thin tube in the high-temperature heat exchanger is formed in a coil shape. By forming the thin tube in the high-temperature heat exchanger into a coil shape, a long vaporization path can be formed with a compact configuration.

Further, a check valve, a gate valve, or a flow rate controller can be provided in the raw material transporting path in or immediately before the vaporization preventing mechanism, so that even in the case of stopping the raw material supply, the upstream side of the check valve or the like can be provided. In addition to preventing the vaporization of the liquid raw material due to the pressure drop, it is possible to prevent the occurrence of clogging or the like due to the generation of precipitates at such a narrow portion.

On the other hand, the vaporization preventing mechanism may be a low-temperature heat exchanger configured to maintain the liquid raw material at a predetermined temperature or lower by using a refrigerant supplied from a constant temperature bath. Prevents thermal effects, maintains a stable state, and enables smooth operation. The vaporization prevention mechanism may be configured to be cooled by a Peltier element, whereby a compact and highly controllable vaporization prevention mechanism can be provided. As the vaporization preventing mechanism or as a part thereof, the raw material transporting path immediately before the vaporizing mechanism may be a heat insulating joint pipe made of a heat insulating material. With this heat insulation effect, the thermal influence of the vaporization mechanism can be effectively prevented.

According to a sixth aspect of the present invention, a carrier gas transport path for flowing a high-temperature carrier gas is merged with a raw material transport path in or near an outlet where the liquid raw material passes through the vaporizing mechanism. The apparatus for vaporizing a liquid raw material according to claim 1, wherein: As a result, it is possible to prevent the temperature of the vaporized raw material from dropping, prevent problems such as deposition of the vaporized raw material, and stabilize the supply of the vaporized raw material. be able to.

The diameter of the narrow tube near the raw material flow outlet of the high-temperature heat exchanger may be enlarged so that the enlarged shape is a divergent nozzle. This prevents the effects of temperature fluctuations and flow disturbances due to pressure fluctuations of the vaporized raw material,
The vaporized raw material flows smoothly to the next step.

According to a seventh aspect of the present invention, there is further provided a cleaning mechanism for flowing a cleaning liquid through the vaporization preventing mechanism and the vaporizing mechanism to clean the inside of the mechanism, and supplying an inert gas to the vaporization preventing mechanism and the vaporizing mechanism. 2. The liquid material vaporizer according to claim 1, further comprising a blow mechanism that blows the raw material or the other material flowing and remaining in the premises.

According to an eighth aspect of the present invention, in the method for operating the liquid raw material vaporizing apparatus according to the first aspect, the liquid raw material is vaporized by flowing the liquid raw material through the vaporization preventing mechanism and the vaporizing mechanism. A vaporization step of supplying the processing chamber, a cleaning step of flowing a cleaning liquid through the vaporization prevention mechanism and the vaporization mechanism to clean the inside of the mechanism, and an inert gas flowing through the vaporization prevention mechanism and the vaporization mechanism. And a blowing step of blowing the remaining raw material or other material. Here, by making the temperature of the vaporization mechanism in the cleaning step different from the temperature of the vaporization mechanism in the vaporization step, more effective cleaning can be performed.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an example, and the present invention is not limited to this embodiment.

The apparatus of the present invention is an apparatus having a remarkable effect when handling a liquid raw material in which an organic metal compound such as titanium, barium, strontium, lead, zirconium or the like is dissolved in an organic solvent.

FIG. 1 is a diagram showing an outline of a vaporizer of the present invention. In FIG. 1, a liquid raw material 2 stored in a raw material container 1 is first sent to a flow controller 5 along a raw material transport pipe 4 by a raw material pump 3. The liquid raw material 2 is a flow controller 5
At the same time, the flow rate is precisely weighed and controlled, and at the same time, the flow rate pulsation fluctuation is flattened and sent to the low temperature heat exchanger 7 which is a vaporization preventing mechanism. The cold water 15 is supplied to the low-temperature heat exchanger 7 from the cold-water constant temperature bath 13, whereby the raw material transport pipe 4, the check valve 6, and the liquid raw material 2 in the low-temperature heat exchanger 7 change due to the temperature change in the peripheral part. Regardless, the temperature is kept uniform and constant.

Next, the liquid raw material 2 is sent to a constant temperature heat exchanger 8 which is a vaporizing mechanism, and is actively vaporized. The high-temperature heat exchanger 8 includes a thin tube (capillary tube) 25 and an outer tube 24.
, A liquid material flows in the narrow tube 25, and the high-temperature heat medium 16 flows around the outer periphery of the narrow tube. Thin tube 2
The inner diameter of 5 is to facilitate heat conduction and vaporization process.
Desirably, it is 3 mm or less.

The thin tube 25 is maintained at a temperature sufficient to uniformly vaporize the raw material and at a temperature at which the raw material is not decomposed or deteriorated by the high-temperature oil 16 supplied from the high-temperature oil thermostat 14. The liquid raw material 2 is a high-temperature heat exchanger 8
By continuously passing through the narrow space of the inner thin tube 25, the temperature is maintained substantially uniformly at a predetermined temperature, and the gas is sequentially vaporized.

The low-temperature heat exchanger 7 as the vaporization preventing mechanism and the high-temperature heat exchanger 8 as the vaporizing mechanism are adjacent to each other with a very small interval. Therefore, the temperature gradient is steep in the raw material transport path during this time, and the liquid raw material instantaneously passes through a temperature range where the raw material is decomposed or deteriorated. As described above, after the raw material does not deteriorate and the solvent is first vaporized and the solute is completely vaporized without precipitating, the surface of the workpiece 11 in the processing chamber 10 is Sent. The raw material transport pipe 4 between the high-temperature heat exchanger 8 and the processing chamber 10 is heated by a heater and maintained at a predetermined temperature so that the vaporized raw material does not liquefy or solidify and precipitate again.

In the present embodiment, the case of one kind of raw material and raw material container is handled, but the present invention is not limited to this. A plurality of raw materials can be guided from a plurality of raw material containers, mixed in a mixing container (not shown), the mixed solution can be vaporized through a vaporization prevention mechanism and a vaporization mechanism, and supplied to a processing chamber.

FIG. 2 is a diagram showing an outline of another embodiment of the vaporizer of the present invention. This apparatus is substantially the same as the vaporizer shown in FIG. 1, except that the configurations of the low-temperature heat exchanger and the high-temperature heat exchanger are slightly different, and a carrier gas line is added. In FIG. 2, a Peltier element 23 is used as a vaporization preventing mechanism, and a gate valve 21 is used instead of a check valve.
Is used.

The high-temperature heat exchanger 8, which is a vaporizing mechanism, has a double cylindrical structure, and the thin tube 25 is wound in a coil shape. A high-temperature oil 16 supplied from a high-temperature oil thermostat 14 flows over the outer periphery of the thin tube 25. I have. After the raw material is completely vaporized in the high-temperature heat exchanger 8, the diameter of the narrow tube 25 as the flow path is enlarged. In order to avoid inadvertent pressure fluctuations and turbulence of the vaporized raw material flow, the diameter of the flow path is enlarged through a divergent nozzle. The high-temperature carrier gas 20 is combined with the raw material transport pipe 4 at the outlet of the high-temperature heat exchanger 24, and the vaporized raw material is entrained.
Is transported onto the surface of the object 11 to be processed.

The surfaces of the thin tubes 25 in the high-temperature heat exchanger 8 are all kept at a uniform and predetermined temperature by the high-temperature oil 16.
The liquid raw material 2 flowing in the narrow space in the narrow tube 25 is quickly and uniformly heated, and is continuously and uniformly vaporized. Since the vaporized raw material passes through a tubing of a predetermined length wound in a coil shape, a predetermined pressure loss is generated. Therefore, the raw material is kept at a predetermined pressure on the upstream side, that is, on the vaporization preventing mechanism. At the same time,
The raw material is cooled by the Peltier element 23 and kept at a predetermined temperature, so that the vaporization of the raw material or the solvent is reliably prevented. Therefore, problems such as partial evaporation and partial precipitation due to differences in boiling points of the substances constituting the liquid raw material are eliminated.

FIG. 3 shows still another embodiment of the present invention. Although the structure of the vaporizer is the same as that of the embodiment of FIG. 2, the difference is that a cleaning mechanism is provided. The present vaporizer can be operated by switching to three processes. That is, the cleaning agent container 29 is arranged in parallel with the raw material container 1, and the raw material gate valve 26 and the cleaning agent gate valve 2
7 is provided so as to be switchable. Further, a blow gas cylinder 31 was connected to the raw material transport path 4 downstream of the gate valve 21 via a blow gas gate valve 28.

In this embodiment, with such a structure, the blow gas gate valve 28 is closed, and the raw material gate valve 26 and the gate valve 21 are opened to vaporize the liquid raw material 2;
The gate valve 21 is closed, the blow gas gate valve 28 is opened, and the blow gas 33 flows to allow the low-temperature heat exchanger (Peltier element) 23 to flow.
A blowing step of blowing the raw material in the raw material transport pipe 4 in the high-temperature heat exchanger 24, a cleaning step of closing the raw material partition valve 26 and the blow gate valve 28, and flowing the cleaning agent 32 to clean the raw material transport pipe 4. Can be individually performed. In this cleaning step, more effective cleaning can be performed by changing the temperature of the high-temperature heat exchanger 8 from the temperature in the vaporization step.

[0035]

As described above, according to the present invention, by using a thin tube for the vaporization mechanism, the liquid raw material can be maintained at a predetermined temperature uniformly and continuously vaporized, and immediately before the vaporization mechanism. By providing a vaporization prevention mechanism, the region through which the raw material passes is clearly divided into a vaporized part and a non-vaporized part, preventing partial evaporation, partial precipitation and deterioration of the composition of the raw material, and efficiently and continuously vaporizing the target raw material. Can be done.

Further, a double cylindrical structure type is used for a high temperature heat exchanger as a vaporization mechanism, and a heat medium is flown between a thin tube (capillary tube) as an inner tube and an outer tube to form a heat exchanger. By keeping the heat transfer surface stable and uniform, the raw material can be vaporized continuously and uniformly by heating the raw material quickly and uniformly.

Further, by using an electric heater as a heat source for heating the tube wall of the thin tube of the high temperature heat exchanger which is a vaporizing mechanism, the temperature of the tube wall of the thin tube can be detected and the output of the electric heater can be controlled with good accuracy. Vaporization can be performed.

Further, by keeping the inside diameter of the thin tube of the high-temperature heat exchanger at 3 mm or less, the raw material can be vaporized satisfactorily by maintaining the raw material uniformly at a predetermined temperature.
Further, by storing the thin tube in a coiled state and storing it in the high-temperature heat exchanger, a compact high-temperature heat exchanger having excellent heat exchange properties can be obtained.

By mixing the raw material with the high-temperature carrier gas near the outlet after passing through the vaporizing mechanism, it is possible to prevent the temperature fluctuation of the vaporized raw material and to prevent the deterioration of the vaporized raw material, such as deterioration. Further, when the diameter of the narrow tube at the outlet of the vaporization mechanism is increased, by making the enlarged shape a divergent nozzle shape, it is possible to prevent the influence of temperature fluctuations and flow disturbances due to pressure fluctuations of the vaporized raw material.

Further, the operating method of the present invention is more efficient by including a vaporizing step of vaporizing the raw material, a blowing step of blowing the raw material remaining in the mechanism when the supply of the raw material is stopped, and a cleaning step of cleaning the inside of the mechanism. Operation can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a vaporizer according to the present invention.

FIG. 2 is a schematic view of a vaporizer according to another embodiment of the present invention.

FIG. 3 is a schematic view of a vaporizer according to still another embodiment of the present invention.

FIG. 4 is a schematic view of a conventional vaporizer.

FIG. 5 is a schematic diagram of a conventional vaporizer.

FIG. 6 is a schematic diagram of a conventional vaporizer.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 raw material container 2 liquid raw material 3 raw material pump 4 raw material transport pipe 5 flow controller 6 check valve 7 low temperature heat exchanger 8 high temperature heat exchanger 9 heater 10 processing room 11 object to be processed 12 vacuum pump 13 cold water constant temperature bath 14 high temperature oil Constant temperature bath 15 cold water 16 high temperature oil 17 raw material flow 18 reaction gas flow 19 exhaust gas flow 20 carrier gas flow 21 gate valve 22 reducer 23 Peltier element (low temperature heat exchanger) 24 outer tube

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Araki 11-1 Haneda Asahimachi, Ota-ku, Tokyo Inside Ebara Corporation

Claims (8)

[Claims] An apparatus for vaporizing a liquid raw material to vaporize a liquid raw material in order to perform a predetermined processing on an object to be processed in a processing chamber and introducing the liquid raw material into the processing chamber, wherein a raw material container for storing the liquid raw material A raw material transport means and a raw material transport path for transporting the liquid raw material, and a vaporization mechanism disposed in the raw material transport path, wherein the vaporization mechanism comprises a thin tube through which the liquid raw material flows, and A heat source for heating from above, and upstream of the vaporization mechanism in the raw material transport path, the liquid raw material in the raw material transport path leading to the vaporization mechanism is subjected to heat of the vaporization mechanism. A vaporization preventing mechanism for preventing the influence of the liquid material from being exerted. 2. The high-temperature heat exchanger has a double-cylindrical structure including the thin tube and an outer tube. A heat medium supplied from a constant-temperature bath flows through the outer tube so that a surface of the thin tube is predetermined. The liquid raw material vaporizer according to claim 1, wherein the heat source is a high-temperature heat exchanger that is maintained at a temperature of (1). 3. The heat source for heating the thin tube of the high-temperature heat exchanger is an electric heater, and the output of the electric heater is variable, and the output of the electric heater is controlled by detecting the temperature of the thin tube. The liquid raw material vaporizer according to claim 1, characterized in that: 4. The apparatus according to claim 1, wherein the inner diameter of the thin tube is 3 mm or less. 5. The liquid raw material vaporizer according to claim 1, wherein the thin tube in the high-temperature heat exchanger is formed in a coil shape. 6. A carrier gas transport path for flowing a high-temperature carrier gas into a raw material transport path at or near an outlet where the liquid raw material passes through the vaporization mechanism. Liquid raw material vaporizer. 7. A cleaning mechanism for flowing a cleaning liquid through the vaporization prevention mechanism and the vaporization mechanism to clean the inside of the mechanism, and an inert gas flowing through the vaporization prevention mechanism and the vaporization mechanism to remain in these premises. The apparatus for vaporizing a liquid raw material according to claim 1, further comprising a blow mechanism for blowing the raw material or another material. 8. The method for operating a liquid raw material vaporizer according to claim 1, wherein the liquid raw material is vaporized by flowing the liquid raw material through the vaporization preventing mechanism and the vaporizing mechanism, and the vaporized raw material is supplied to the processing chamber. A cleaning step of flowing a cleaning liquid through the vaporization prevention mechanism and the vaporization mechanism to clean the inside of the mechanism; and flowing an inert gas through the vaporization prevention mechanism and the vaporization mechanism to leave a raw material or other material remaining in these premises. A method for operating a vaporizer for a liquid raw material, comprising: