JP2016143798A - Vaporizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vaporizer which achieves excellent vaporization efficiency of nearly 100% and prevents secular change in the vaporization amount and concentration.SOLUTION: A vaporizer A according to the invention includes: an atomizer 7 which atomizes a liquid material L to spray the liquid material L; a hollow outer tube 1 connected with a spray port 73 of the atomizer 7; an inner tube 2 housed in the outer tube 1; and a heater 4 (9) provided in at least one of an outer side of the outer tube 1 and an inner side of the inner tube 2. A tip head part 2a of the inner tube 2 is disposed so as to be oriented in a direction of the spray port 73, and an atomization space M is provided between the spray port 73 and the tip head part 2a. A vaporization gap 3 communicating with the atomization space M is provided between an inner peripheral surface of the outer tube 1 and an outer surface of the inner tube 2. The tip head part 2a of the inner tube 2 is formed into a hemispherical shape or a conical shape. An arc shaped projection 81 or an arch shaped groove 82 is formed from a top part P of the tip head part 2a to the outer surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vaporizer excellent in vaporization efficiency, particularly for semiconductor manufacturing and optical waveguide formation.

There are wet oxidation and dry oxidation as types of thermal oxidation methods for semiconductor materials such as Si and SiC. Water is used in wet oxidation. H ₂ O is flowed into the furnace as gas (water vapor), and oxygen in the water is used for growth of the oxide film. This feature has a high oxidation rate. Therefore, this method is used when a thick film is required. On the other hand, dry oxidation uses oxygen gas for oxide film growth. This is the opposite of wet oxidation, and the growth rate is slow. In recent years, hydrogen peroxide (H ₂ O ₂ ) has been used instead of water (H ₂ O) in order to further increase the growth rate of oxide films. On the other hand, there is formation of an optical waveguide as an application other than the semiconductor. (See Patent Document 1). In this case, the deposition of silicon dioxide (SiO ₂ ) having a thickness of 10 to 25 μm requires a long deposition time in the oxidation method using H ₂ O. If hydrogen peroxide (H ₂ O ₂ ) is used instead of H ₂ O, the time can be significantly reduced.

  For this purpose, it is necessary to vaporize a large amount of hydrogen peroxide and send it to the reactor. An apparatus as shown in Patent Document 1 has been proposed as such an apparatus.

JP 2001-337240 A

  The vaporizer described in Patent Document 1 that vaporizes hydrogen peroxide water to generate oxidizing gas is a heater from the outside of the lower half of the vaporizer of a hollow spherical container similar to a flask containing hydrogen peroxide water. The hollow spherical container is heated to 100 to 130 ° C., and the vaporized water vapor gas containing hydrogen peroxide gas flows into the reaction furnace through the gas supply pipe. This apparatus simply heats and vaporizes the hydrogen peroxide solution, and the disadvantage is that the concentration of hydrogen peroxide changes as the hydrogen peroxide solution evaporates in the vaporizer. Furthermore, it is difficult to keep the flow rate of hydrogen peroxide constant, and the flow rate of how much is flowing is unknown.

  The present invention has been made in view of such conventional problems, and the object thereof is far superior to the conventional example in vaporization efficiency of almost 100%, and there is no change with time in vaporization amount and concentration. To provide a vaporizer.

The vaporizer A according to the invention described in claim 1 is:
An atomizer 7 that atomizes and blows off the liquid raw material L;
A hollow outer tube 1 to which the atomizing port 73 of the atomizer 7 is connected;
An inner tube 2 housed in the outer tube 1;
A heater 4 (9) provided on at least one of the outer side of the outer tube 1 or the inner side of the inner tube 2;
The tip portion 2a of the inner tube 2 is disposed so as to face the spray port 73, and an atomization space M is provided between the spray port 73 and the tip portion 2a.
Between the inner peripheral surface of the outer tube 1 and the outer surface of the inner tube 2, a vaporizing gap 3 communicating with the atomizing space M is provided,
The tip head 2a of the inner tube 2 is formed in a hemispherical or conical shape, and an arc-shaped protrusion 81 or an arc-shaped groove 82 is formed from the top P of the tip head 2a toward the outer surface. And

  According to a second aspect of the present invention, in the vaporizer A according to the first aspect, the atomizer 7, the inner tube 2, and the outer tube 1 are formed of quartz glass.

  Since the vaporizer A according to the present invention is provided with the “atomization space M” and the “vaporization gap 3” communicating with the “atomization space M”, the liquid raw material L from the atomizer 7 is atomized in the “atomization space M”. Then, it flows along the tip head 2a, flows into the sufficiently small “vaporization gap 3”, and is rapidly vaporized by the heater 4 (9).

  At this time, the distal end head 2a of the inner tube 2 is formed in a hemispherical shape or a conical shape, and an arc-shaped protrusion 81 or an arc-shaped groove 82 is formed from the top P of the distal end head 2a toward the outer surface. Therefore, the fluid containing the mist-like fluid K flowing along the tip head portion 2a curves along the arc-shaped protrusion 81 or the arc-shaped groove 82, and the swirl flow GR swirling around the inner tube 2 in the “vaporization gap 3”. Flow to form. Thus, a sufficient time for vaporization can be secured, and a constant amount of vaporized gas G2 is always supplied to the next step.

  The vaporizer A of the present invention can be directly connected to the liquid flow rate controller E, and can vaporize the hydrogen peroxide solution transported into the vaporizer A at a high rate of almost 100%. Therefore, hydrogen peroxide gas can be generated quantitatively and at a constant concentration.

It is the front view which carried out a cross section of a part of one example of the present invention. FIG. 5 is a cross-sectional view taken along the line XX in FIG. 4. It is a YY cross-sectional arrow view of FIG. It is sectional drawing of FIG. It is an expansion perspective view of the front-end | tip head of the inner tube of this invention. It is an expansion perspective view of the front-end | tip head of the inner tube of this invention. It is an expansion perspective view of the further another example of the front-end | tip head of the inner tube of this invention. It is a block diagram in the semiconductor manufacturing apparatus using the vaporizer | carburetor of this invention.

  The present invention will be described below with reference to the drawings. The vaporizer A includes an atomizer 7, an outer tube 1, an inner tube 2, and a heater 4 (9). The liquid raw material L to which the vaporizer A is applied may be anything as long as it is vaporized and used (for example, various liquid raw materials used for semiconductor manufacturing). . When the vaporizer A is used for vaporizing hydrogen peroxide water and an extremely high purity hydrogen peroxide-containing water vapor gas G2 is required as in a semiconductor manufacturing apparatus, the hydrogen peroxide-containing water vapor gas G2 is converted into a hydrogen peroxide-containing water vapor gas G2 in a high-temperature environment. The atomizer 7, the outer tube 1 and the inner tube 2 are made of “quartz glass” which is not violated. In other fields, it is also possible to use a heat resistant glass such as Pyrex (registered trademark) glass or a corrosion resistant metal such as Hastelloy or stainless steel.

  The atomizer 7 is inclined to the spray gas pipe 7a connected to the end of the outer tube 1 and to the spray gas pipe 7a at a right angle or an angle close thereto or not shown, but in the flow direction of the atomized gas. A main feed hole 7c through which the atomized gas passes, and the liquid feed inlet pipe 7b is connected to the main feed hole 7c. A hole 7d is formed. The inner diameter of the main supply hole 7 c is larger than the inner diameter of the sub supply hole 7 d, and the outlet is narrowed down to form a spray port 73. The outlet portion of the atomizing gas pipe 7 a of the atomizer 7 is connected to the inner tube 2.

  The outer tube 1 is a cylindrical hollow tube, one end of which is closed, a spray gas tube 7a of an atomizer 7 is connected to the closed end 1a, and a spray port 73 is opened. An outlet nozzle 11 communicating with a vaporizing gap 3 described later is connected to the outer peripheral surface of the outer tube 1 opposite to the closed end 1a.

  The inner tube 2 has a distal end head 2a which is the insertion end side closed, is formed in a hemispherical shape, reaches the outer edge from the apex P of the distal end head 2a, and faces the outer surface of the inner tube 2 3 The arc-shaped ridges 81 of the book are formed at the same angle and in the same direction (the convex curve direction projects clockwise as shown in FIG. 2). The arc-shaped ridge 81 is formed of a thin quartz glass rod and is welded to the portion. The number of the arc-shaped protrusions 81 is not particularly limited, and may be one or more, but is preferably at least three.

  It is preferable that a straight line (outer tangent) that contacts the end of the arc-shaped protrusion 81 that reaches the outer edge of the inner tube 2 is a tangent to the outer surface of the inner tube 2 or a line close thereto. In the embodiment shown in the figure, the shape of the tip head 2a is hemispherical, but of course it is not limited to this, and may be a spheroid, a paraboloid or a cone. Further, although the arc-shaped protrusion 81 is used here, an arc-shaped groove 82 that is curved in the same direction (the convex curve direction is curved clockwise as shown in FIG. 2) may be formed. In any case, it is preferable to provide a plurality (FIG. 7).

  The other end of the inner tube 2 is open, and the inner heater 9 is inserted. Further, at least three minute projections 6 on the same circumference are provided in two stages on the outer circumferential surface of the inner tube 2, and when the inner tube 2 is inserted into the outer tube 1, these minute projections 6. Comes into contact with the inner peripheral surface of the outer tube 1 and forms a uniform and sufficiently narrow vaporization gap 3 between the inner tube 2 and the outer tube 1 over the entire circumference. The vaporization gap 3 is connected to the outlet nozzle 11 as described above on the heater insertion end side. The outlet nozzle 11 is connected to a mass flow controller S for supplying the vaporized gas G2 by a mass flow rate to a reaction furnace for silicon substrate oxidation, for example.

  The width W of the vaporization gap 3 is not particularly limited, but the width W is preferably within a range in which a temperature boundary layer having a high heat transfer coefficient is formed in terms of vaporization efficiency. That is, the temperature of the flowing fluid Q flowing through the vaporizing gap 3 is such that the temperature of the outer peripheral surface of the inner tube 2 or the inner peripheral surface of the outer tube 1 is a wall surface temperature, the fluid temperature gradually decreases as the distance from the wall surface increases. At a certain temperature (uniform flow temperature). The range in which the temperature reaches a certain temperature from the wall surface is the temperature boundary layer, and the width W of the vaporization gap 3 is preferably in this range.

  The opening ends on the heater insertion side of the inner tube 2 and the outer tube 1 are fused over the entire circumference, and the opening end on the heater insertion side of the vaporization gap 3 is closed over the entire circumference. The tip head 2a of the inner tube 2 housed in the outer tube 1 faces the spray port 73, and an atomization space M is formed between the closed end 1a where the spray port 73 is provided and the tip head 2a. Is provided. The vaporization gap 3 communicates with the atomization space M over the entire circumference.

  An electric heater is used as the heating device, and an inner heater 9 and an outer heater 4 are used in the illustrated embodiment. Of course, as long as the heating is sufficient, either one may be used. The inner heater 9 is inserted inside the inner tube 2 and bonded to the inner peripheral surface of the inner tube 2 with an adhesive paste 5 having excellent thermal conductivity. Similarly, the outer heater 4 is bonded to the outer peripheral surface of the outer tube 1 with an adhesive paste 5. The inner heater 9 is equipped with a temperature sensor 10 to control the temperature of the inner heater 9. The outer heater 4 may be controlled so as to be linked to the temperature sensor 10 of the inner heater 9, or although not shown, a temperature sensor may be prepared independently.

  Next, the operation of the vaporizer A of the present invention will be described. FIG. 8 shows an example of the configuration of a semiconductor manufacturing apparatus using the vaporizer A of the present invention. The liquid source L is sent out by the pressurized gas G0 in which the liquid source L (hydrogen peroxide solution in this embodiment) is stored. A raw material tank T connected to the raw material tank T, connected to a liquid flow rate controller E for sending the supplied liquid raw material L at a constant flow rate, and an atomizing gas supply source such as nitrogen gas or oxygen gas. A mass flow controller S for sending G1 by the mass flow rate, a liquid raw material introduction pipe 7b for receiving the liquid raw material L sent from the liquid flow rate controller E, and an atomizing gas pipe 7a for receiving the atomized gas G1 from the mass flow controller S. And an atomizer 7 constituted by the above-mentioned is provided at the inlet portion, and for example, a fixed amount of processing gas G2 (hydrogen peroxide-containing water vapor gas in this embodiment) is stably supplied to a reactor H for oxidizing a silicon substrate. It is composed of a vaporizer A.

  In this apparatus, when the heater 4 (9) is energized and the outer tube 1 and the inner tube 2 are heated to a predetermined temperature, the liquid material L (hydrogen peroxide solution in this embodiment) is supplied to the atomizer 7 as the liquid material supply port 72. At the same time, the atomized gas G1 is press-fitted into the gas supply port 71. As a result, the fluid raw material L is sprayed into the atomizing space M from the spray port 73 as the mist fluid K.

  The mist-like fluid K collides with the spherical tip head 2a of the inner tube 2 and flows along the arc-shaped protrusion 81 (or arc-shaped groove 82) of the tip head 2a. It flows in the tangential direction of the outer circumference of the inner tube 2 or a direction close thereto at the outer peripheral edge of the tip head 2a, and advances in the vaporization gap 3 toward the outlet nozzle 11 while turning around the inner tube 2. That is, the swirl flow GR is generated in the vaporization gap 3. Thereby, a sufficient heating time can be secured. During this time, when the entire vaporization gap 3 is a temperature boundary layer, the swirling flow GR is heated to a temperature close to the wall surface temperature and rapidly vaporized, and is discharged from the outlet nozzle 11 to be mass flow controller S. To be supplied.

  In addition, when the atomizer 7, the outer tube 1 and the inner tube 2 of the vaporizer A are formed of “quartz glass”, even if the liquid raw material L is hydrogen peroxide, it is not violated. It can be applied to surface oxidation of a substrate.

  A: vaporizer, L: liquid raw material, E: liquid flow controller, G0: pressurized gas, G1: atomized gas, G2: vaporized gas, GR: swirling flow, H: reactor, K: atomized fluid, M: atomization space, P: top, Q: flow fluid, S: mass flow controller, T: raw material tank, W: width of vaporization gap, 1: outer tube, 1a: closed end, 2: inner tube 2a: tip head, 3: gap for vaporization, 4: outer heater, 5: paste, 6: protrusion, 7: atomizer, 7a: spray gas pipe, 7b: liquid raw material introduction pipe, 7c: main supply hole, 7d : Sub-supply hole, 9: inner heater, 10: temperature sensor, 11: outlet nozzle, 71: gas supply port, 72: liquid raw material supply port, 73: spraying port, 81: arc-shaped ridge, 82: arc-shaped groove.

Claims (2)

An atomizer that atomizes and blows off liquid ingredients;
A hollow outer tube to which the atomizer spray port is connected;
An inner tube stored in the outer tube;
It is composed of a heater provided on at least one of the outside of the outer tube or the inside of the inner tube,
The tip of the inner tube is disposed so as to face the spray port, and an atomization space is provided between the spray port and the tip of the head.
A vaporizing gap communicating with the atomization space is provided between the inner peripheral surface of the outer tube and the outer surface of the inner tube,
The carburetor characterized in that the tip head portion of the inner tube is formed in a hemispherical shape or a conical shape, and an arc-shaped protrusion or arc-shaped groove is formed from the top of the tip head portion toward the outer surface.   The vaporizer according to claim 1, wherein the atomizer, the inner tube, and the outer tube are made of quartz glass.