JP2000355765A - Vaporizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vaporizer which is capable of uniformly maintaining the state of a portion where solution raw material is vaporized and vaporizing the solution raw material in a stable state. SOLUTION: This vaporizer has a pressure barrier part 4 where the opposite surfaces of a pair of solution guide members 2 and 3 are arranged to face each other apart a prescribed spacing, a solution raw material supply part 6 which is opened in the central part of the pressure barrier part 4, a vaporization chamber 5 which covers the circumference of the pressure barrier part 4, a carrier gas introducing part 10 which introduces the carrier groups into the vaporization chamber 56, a vaporizing raw material delivery part 8 which leads the vaporizing raw material out of the vaporization chamber 5 by entraining the same in the carrier gas, a heater which heats the pressure barrier part 4 and a thermocouple for control of the heater.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vaporizer, and more particularly to a vaporizer provided in a raw material supply system of a CVD apparatus, which vaporizes a solution raw material obtained by dissolving a solid raw material having a low vapor pressure in a solvent. For vaporizers.

[0002]

2. Description of the Related Art As a raw material for forming a thin film in a CVD apparatus, a solid raw material having a low vapor pressure, for example, Ba (DPM) ₂ or S
When r (DPM) ₂ is used, these solid raw materials are dissolved in an appropriate solvent to form a solution raw material, and this solution raw material is heated and vaporized in a vaporizer, transported by a carrier gas, and transferred to a reaction furnace. Methods of supplying are known. This method is known to suppress the deterioration of the raw material due to heat as compared with the method of directly heating the solid raw material, and to improve the film forming rate.

[0003] In the vaporization of a solution raw material in a vaporizer, a solution raw material pressurized to a pressure at which a solvent does not boil at a predetermined heating temperature is supplied to a pressure barrier portion heated to a predetermined temperature and passed through the pressure barrier portion. This is carried out by heating the solution raw material and evaporating the solid raw material together with the solvent by the pressure drop after passing through the pressure barrier section.

As a pressure barrier in such a carburetor, those having various structures have conventionally been used. A plurality of laminated thin disks (disks) are housed in a vaporization chamber of a carburetor main body, and a heater is provided. While heating the laminated disk to a predetermined temperature by a pressing member (anvil) via a spring at a predetermined pressure, a solution raw material at a predetermined pressure is supplied into a through hole at the center of the disk,
A laminated disk type in which the solution raw material oozes out from between the contact surfaces of the disk and is vaporized at the outer peripheral edge of the disk is often used. Since the vaporizer adopting the laminated disk type presses the laminated disks via a spring, the supply pressure of the solution raw material is adjusted to an optimum pressure by appropriately setting the pressing force (lamination pressure). Can be used to vaporize various types of raw materials.

[0005]

However, in the above-described vaporizer of the laminated disk type, unless the laminating pressure of the disks and the supply state of the solution material are properly maintained, only the solvent evaporates between the disks. Solids may be generated and remain between the disks. When solid matter is generated between the disks as described above, the disks are fixed to each other by the solid matter, and the space between the disks is closed by the solid matter.

On the other hand, the pump for supplying the solution raw material to the vaporizer always sends out a constant amount of the solution raw material in order to keep the raw material supply amount to the reaction furnace constant. If the flow of the solution raw material during this period is hindered, the pressure of the solution raw material supplied to the vaporizer increases with an increase in the flow path resistance of the disk portion.

[0007] When the supply pressure of the solution raw material rises in this way, the balance with the pressing force of the spring pressing the disk via the anvil is broken, and the anvil is pushed back in the direction of compressing the spring. The entire stacked disk moves to the anvil side, and a gap is generated between the stacking end of the disk, particularly, the disk on the solution material supply side and the bottom of the vaporization chamber, and a phenomenon occurs in which the solution material is ejected from the gap. .

[0008] Since the ejection of such a solution raw material is completely different from the oozing from between the contact surfaces of the disk,
The solution raw material is vaporized in a state contrary to the design intention. In addition, the interaction with the spring repeats the cycle of flow rate decrease → pressure rise → liquid ejection → pressure decrease → flow rate decrease. Therefore, pulsation occurs in the supply pressure and supply amount of the solution raw material, and the amount of vaporization increases. Since the film becomes unstable, it has a serious effect on the film forming operation, and a good thin film cannot be obtained.

Also, when a cleaning solvent for cleaning the inside of the vaporizer is introduced in a state where the space between the disks is closed with a solid matter, the cleaning solvent is ejected from a portion where a gap is likely to be generated. It becomes difficult to thoroughly clean the whole.

Further, those using a porous body or a thin tube as a pressure barrier portion are also known, but these are difficult to uniformly heat, easily block a flow path by solid matter, and have a dead space. There are many problems.

Accordingly, an object of the present invention is to provide a vaporizer capable of maintaining a uniform state of a portion for vaporizing a solution raw material and vaporizing the solution raw material in a stable state.

[0012]

In order to achieve the above object, a vaporizer according to the present invention comprises a pressure barrier formed by arranging opposed surfaces of a pair of solution guide members at a predetermined interval; A solution source supply port provided at the center of the section, a vaporization chamber covering the periphery of the pressure barrier section, a carrier gas introduction section for introducing a carrier gas into the vaporization chamber, and causing the vaporized material to accompany the carrier gas. And a heater for heating the pressure barrier section.

Further, the vaporizer according to the present invention is characterized in that the carrier gas inlet is provided at a plurality of positions near the outer periphery of the pressure barrier so that the carrier gas flows along the outer periphery of the pressure barrier. And the heater is provided inside each of the solution guide members, and further,
A temperature measuring means for controlling a heater is provided inside each of the solution guide members.

[0014]

1 to 5 show an embodiment of a vaporizer according to the present invention. FIG. 1 is a sectional view taken along line II of FIG. 2, and FIG. 2 is a side of a first solution guide member. FIG. 3 is a schematic view for explaining an installation state of a heater and a thermocouple in FIG.
FIG. 4 is a schematic view for explaining an installation state of a heater and a thermocouple on a solution guide member side, FIG. 4 is a sectional view of a main part showing a pressure barrier portion, and FIG. 5 is a front view of a vaporization chamber bottom surface.

The vaporizer 1 shown in this embodiment has a first solution guide member 2 having a concave cross section formed by cutting a columnar metal such as stainless steel into a predetermined shape, and a first liquid guide member 2 having a convex cross section. 2 is formed by combining the second solution guide member 3 with the bottom surface 2a of the concave portion of the first solution guide member 2;
The pressure barrier portion 4 is formed by arranging the protruding portion front end surface 3 a of the solution guide member 3 at a predetermined interval, and the inner periphery of the concave portion of the first solution guide member 2 and the second solution guide member 3 are formed. A vaporization chamber 5, which is a closed space surrounding the pressure barrier portion 4, is formed between the outer periphery of the convex portion.

The distance between the opposing surfaces of the pressure barrier section 4 is set so that the vaporization point of the solution raw material is located at the outer peripheral portion of the pressure barrier section 4, and depends on the properties of the solution raw material to be vaporized. Although different, it is usually set to 1 mm or less, and is set in consideration of the thermal expansion of each member when heated to a predetermined temperature.

The first solution guide member 2 has a solution raw material supply section 6 opening at the center of the pressure barrier section 4, a carrier gas supply section 7 for supplying a carrier gas to the vaporization chamber 5, and a vaporization chamber 5. A vaporized raw material delivery section 8 for delivering the raw material, a heater insertion section H for inserting a heater, and a thermocouple insertion section S for inserting a thermocouple as a temperature measuring means are provided at predetermined positions, respectively. The second solution guide member 3 is provided with a heater insertion portion H and a thermocouple insertion portion S at predetermined positions.

As shown in FIG. 2, the first solution guide member 2 has four inner heaters H1 to H4 for heating the pressure barrier portion 4 and a heater for heating the vaporizing chamber 5 from the outer periphery. The four heaters H5 to H8 on the outer peripheral portion of are respectively inserted into the second solution guide member 3, as shown in FIG.
Two heaters H9 and H for heating the pressure barrier section 4
10 are inserted.

Furthermore, a thermocouple S1 for measuring the temperature of the pressure barrier portion 4 from the first solution guide member side is inserted into the first solution guide member 2, and the pressure barrier portion 4 is inserted into the second solution guide member 3. A thermocouple S2 for measuring the temperature from the second solution guide member side and a thermocouple S3 inserted to the first solution guide member 2 and measuring the outer peripheral temperature of the vaporization chamber 5 are inserted.

These thermocouples are used for heater control for controlling each heater in accordance with each measured temperature, and the heaters H1 to H4 are controlled by the thermocouple S1.
The heaters H9 and H10 are turned on by the thermocouple S2.
Controls the heaters H5 to H8, respectively.

Further, inside the first solution guide member 2,
A carrier gas flow path 9 communicating with the carrier gas supply unit 7 is provided in a ring shape, and further communicates with the carrier gas flow path 9 and the vaporization chamber 5. A plurality of carrier gas introduction portions 10 are provided at equal intervals to eject the carrier gas flowing into the passage 9 from the outer periphery of the pressure barrier portion 4. Also,
A ring-shaped carrier gas guide groove 11 connecting the carrier gas introduction portions 10 is provided on the concave portion bottom surface 2a.

As shown in the system diagram of FIG. 6, the vaporizer 1 thus formed has a carrier gas supply pipe 22 via a flow rate controller 21 to a carrier gas supply section 7 and a raw material to a vaporized raw material delivery section 8. A reaction furnace 25 for forming a film on a substrate 24 via a gas supply pipe 23 is connected to a solution raw material supply section 6 via a solution raw material supply pipe 26 and a pump 27, and a solution raw material container 28 is connected thereto. The thermocouple is used with a thermocouple connected to a power supply unit (not shown) and a measuring instrument (not shown).

The source gas supply pipe 23 has a vent pipe 3 switched by a pair of switching valves 29a and 29b.
0 is provided. In addition, the solution raw material supply pipe 26 has:
A washing solvent container 34 is connected via a flow path switching valve 31, a solvent supply pipe 32 and a pump 33, and a pressure gauge 35 for measuring the pressure in the solution raw material supply pipe 26 is provided.

Then, the heater is energized to apply pressure to the pressure barrier portion 4.
And the surroundings thereof are heated to a predetermined temperature, and further, the carrier gas is supplied from the carrier gas supply pipe 22 at a predetermined flow rate, and the pump 27 is operated to move the solution raw material in the solution raw material container 28 from the solution raw material supply pipe 26. The solution is supplied to the solution raw material supply section 6 of the vaporizer 1. Thereby, the solution raw material is supplied to the pressure barrier portion 4 from the solution raw material supply port opened at the center of the pressure barrier portion 4 through the solution raw material supply portion 6, and the pressure barrier portion 4 set at a predetermined minute interval is supplied to the pressure barrier portion 4. Flow, vaporization chamber 5 from outer periphery
The entire amount is vaporized due to the temperature rise due to heating and the pressure drop at the time of leaching.

At this time, the pressure barrier portion 4 is formed between the opposing surfaces 2a, 3a of the blocks 2, 3 in a state where the pair of the first solution guide member 2 and the second solution guide member 3 are fixed. The interval between the pressure barrier portions 4 can be reliably maintained at a predetermined size, and the solution raw material can flow uniformly throughout the pressure barrier portions 4. Thereby, it is possible to generate a smooth liquid flow in the pressure barrier section 4, to suppress the generation of solids in the pressure barrier section 4, and to almost eliminate dead space. Further, even if the pressure fluctuates, the distance between the pressure barrier portions 4 does not fluctuate, and the solution raw material can be vaporized in a stable state.

On the other hand, the carrier gas supplied to the carrier gas supply unit 7 flows into the carrier gas introduction unit 10 through the carrier gas flow path 9, and the carrier gas is supplied from each carrier gas introduction unit 10 through the carrier gas guide groove 11. It flows out to the outer periphery of the barrier portion 4. At this time, by appropriately covering the carrier gas guide groove 11 with the outer periphery of the protruding portion front end face 3a of the second solution guide member 3, the carrier gas introduction section 10 allows the vaporization chamber 5
Carrier gas to be introduced into the carrier gas guide groove 1
1, and can be ejected from the entire outer periphery of the pressure barrier portion 4.

By flowing the carrier gas as described above, the raw material leached and vaporized from the pressure barrier portion 4 can be brought into effective contact with the carrier gas.
The vaporized raw material can be uniformly dispersed in the carrier gas, and a constant amount of the raw material can be sent out from the vaporizer 1 toward the reaction furnace 25.

Further, since the heating of the pressure barrier portion 4 is performed not only from around the vaporization chamber 5 but also from both the first solution guide member 2 and the second solution guide member 3, the pressure barrier portion 4 and the vaporization portion are heated. The entire chamber 5 can be uniformly heated.
As a result, it is possible to prevent the temperature from locally increasing or decreasing in the pressure barrier section 4 and the vaporization chamber 5, so that the thermal decomposition of the raw material in the high temperature portion and the re-solidification of the raw material in the low temperature portion can be prevented. Can be reliably prevented. As a result, the vaporizer 1 can be effectively cleaned with the cleaning solvent.

Further, in the conventional vaporizer, the solid matter generated in the vaporization chamber needs to be discharged to the outside at the time of cleaning, and the vaporized raw material delivery section is provided at the lower side of the vaporization chamber. In some cases, the substance may flow out into the pipe through the vaporized raw material delivery section and adhere to the valve seat to generate a flow. However, in the vaporizer 1 shown in the present embodiment, as described above, the pressure barrier section Since the generation of solids and re-coagulated matter in the vaporization chamber 4 and the vaporization chamber 5 can be suppressed to a low level, the vaporized raw material delivery section 8 can be provided on the upper side of the vaporization chamber 5. Thereby, even if a solid or the like is generated in the vaporization chamber 5, it is possible to prevent the solid from flowing out into the pipe through the vaporized raw material delivery unit 8.

FIG. 7 is a schematic sectional view showing another example of the shape of the vaporizer of the present invention. This vaporizer is formed by a first solution guide member 51 having a cylindrical shape and a second solution guide member 53 having a ring-shaped groove serving as a vaporization chamber 52. A plurality of carrier gas inlets 55 are provided at positions where the solution raw material supply unit 54 communicates with the vaporization chamber 52 at the center, and a heater insertion unit H and a thermocouple insertion unit S are provided at predetermined positions, respectively. The two-solution guide member 53 is provided with a vaporized raw material delivery section 56 communicating with the vaporization chamber 52, a heater insertion section H and a thermocouple insertion section S, respectively.

The first solution guide member 51 and the second solution guide member 53 are brought into close contact with the inner peripheral surface 51a of the first solution guide member 51 by bringing the outer peripheral wall front end surface 53a of the second solution guide member 53 into close contact. When assembled, a pressure barrier portion 57 with a predetermined interval is formed between the inner peripheral wall front end surface 53b of the second solution guide member 53 and the inner surface 51a of the first solution guide member 51.

The vaporizer thus formed can also provide the same functions and effects as those of the above embodiment.

FIG. 8 shows an example in which an auxiliary member is used to maintain the distance between the surfaces in the pressure barrier portion.
That is, a plurality of holding holes 65 for inserting and holding the rod-shaped spacer 64 are provided at appropriate positions on the opposing surfaces of the members 62 and 63 forming the pressure barrier portion 61, respectively. By inserting the spacer 64 and fastening the two members 62 and 63 with bolts or the like, the pressure barrier portion 61 is maintained at a predetermined interval. Note that a solution raw material supply unit 66 is provided at the center of one of the members.

As described above, the configuration and shape of the members constituting the vaporizer can be arbitrarily set as required.
In addition, by inserting a heater and a thermometer (thermocouple) into both members forming a pressure barrier portion formed between parallel planes at extremely narrow intervals, the temperature of the pressure barrier portion can be quickly and reliably controlled. Can be. Further, by forming the carrier gas to flow along the solution raw material vaporizing portion on the outer periphery of the pressure barrier portion, the vaporized raw material can be sent out from the vaporizer in a state of being uniformly mixed with the carrier gas.

By forming the pressure barrier portion into a circular shape as described above, the distance from the solution material supply portion (solution material supply port) to the solution material vaporization portion around the pressure barrier portion can be equalized. However, it is also possible to form a polygonal shape.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Using a vaporizer having the structure shown in FIGS. 1 to 5 and a commercially available vaporizer having a conventional structure of a laminated disk, Ba (DPM) ₂ and Sr which are solid raw materials having a low vapor pressure are used.
(DPM) ₂ was added to the solvent THF at 0.1 mol /
An experiment was conducted in which a solution raw material dissolved in L was supplied and vaporized. The gap at the pressure barrier was set to 10 μm. In addition,
The supply amount of the carrier gas, the set temperature of the vaporizer, the capacity of the solution raw material pump, and the like were set as one condition for both vaporizers.

FIG. 9 shows the state of the flow rate fluctuation of the solution raw material in the vaporizer of this embodiment, and FIG. 10 shows the state of the flow rate fluctuation of the solution raw material in the conventional vaporizer. As is clear from both figures, it can be seen that the vaporizer of the present embodiment can maintain a stable state for a long time. In the case of the conventional device, the operation was stopped about 10 minutes after pulsation occurred.

[0038]

As described above, according to the vaporizer of the present invention, the vaporizer can be formed with a small number of parts, and the solution raw material can be vaporized in a stable state.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a vaporizer according to the present invention, and is a sectional view taken along line II of FIG.

FIG. 2 is a schematic diagram for explaining an installation state of a heater and a thermocouple on a first solution guide member side.

FIG. 3 is a schematic diagram for explaining an installation state of a heater and a thermocouple on a second solution guide member side.

FIG. 4 is a sectional view of a main part showing a pressure barrier portion.

FIG. 5 is a front view of a vaporization chamber bottom surface.

FIG. 6 is a system diagram showing a use state of the vaporizer.

FIG. 7 is a sectional view of a main part showing another example of the shape of the vaporizer of the present invention.

FIG. 8 is a cross-sectional view of a main part showing an example in which an inter-surface distance in a pressure barrier portion is held by an auxiliary member.

FIG. 9 is a diagram showing a state of a flow rate fluctuation of a solution raw material in the vaporizer of the present invention. FIG. 3 is a system diagram showing a use state of the vaporizer.

FIG. 10 is a diagram showing a state of a flow rate fluctuation of a solution raw material in a conventional vaporizer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vaporizer, 2 ... 1st solution guide member, 3 ... 2nd solution guide member, 4 ... Pressure barrier part, 5 ... Vaporization chamber, 6 ... Solution raw material supply part, 7 ... Carrier gas supply part, 8 ... Vaporized raw material Delivery section, 9: Carrier gas flow path, 10: Carrier gas introduction section, 11: Carrier gas guide groove, 21: Flow controller,
22: carrier gas supply pipe, 23: source gas supply pipe, 2
4 ... substrate, 25 ... reactor, 26 ... solution raw material supply pipe, 27
... Pump, 28 ... Solution raw material container, 29a, 29b ... Switching on / off valve, 30 ... Vent pipe, 31 ... Flow path switching valve, 32 ... Solvent supply pipe, 33 ... Pump, 34 ... Washing solvent container, 35 ...
Pressure gauge, 51: first solution guide member, 52: vaporization chamber, 5
3: second solution guide member, 54: solution raw material supply unit, 55
... Carrier gas introduction section, 56 ... Vaporized material delivery section, 57 ...
Pressure barrier section, 61 ... Pressure barrier section, 62, 63 ... Member, 6
4: spacer, 65: holding hole, 66: solution raw material supply section, H: heater insertion section, H1 to H10: heater, S
... thermocouple insertion part, S1 to S16 ... thermocouple

Claims (4)

[Claims] A pressure barrier formed by arranging opposed surfaces of a pair of solution guide members at predetermined intervals, a solution material supply port provided at a central portion of the pressure barrier, and the pressure barrier. A vaporizing chamber that covers the periphery of the fuel cell, a carrier gas introducing unit that introduces a carrier gas into the vaporizing chamber, a vaporized raw material sending unit that is brought out of the vaporizing chamber with the vaporized raw material accompanying the carrier gas, and heating the pressure barrier unit A vaporizer characterized by comprising a heating device. 2. The apparatus according to claim 1, wherein a plurality of the carrier gas introduction portions are provided near the outer periphery of the pressure barrier portion so that the carrier gas flows along the outer periphery of the pressure barrier portion. Vaporizer. 3. The vaporizer according to claim 1, wherein the heater is provided inside each of the solution guide members. 4. The vaporizer according to claim 3, wherein temperature measuring means for controlling a heater is provided inside each of the solution guide members.