JPH07106254A - Device and method for vaporization and supply equipment for liquid raw material - Google Patents

Abstract

PURPOSE:To enable stable vaporization when supply amount of liquid raw material is increased, in the case of vaporization and evaporation of supplied liquid raw material. CONSTITUTION:In a vaporization supplying method for liquid raw material wherein liquid raw material L is supplied to a vaporization chamber 13 while carrier gas is supplied to the vaporization chamber 13, the liquid raw material L which permeates into the vaporization chamber 13 is vaporized and evaporated, and mixture gas Kn of the carrier gas and the vaporized material gas is supplied to a reaction chamber, the carrier gas is jetted toward a liquid exit 23a into which the liquid raw material L permeates, and the vicinity of the liquid exit 23a is set in the state of reduced pressure, by increasing the flow velocity of the carrier gas in the vicinity of the liquid exit 23a. Thereby vaporization and evaporation of the liquid raw material L are accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid source vaporizer and a supply method thereof for controlling the flow rate of a liquid source and vaporizing it in the field of liquid chemicals including VLSI in the semiconductor manufacturing process. Regarding improvement.

[0002]

2. Description of the Related Art A VLSI manufacturing process will be described below as an example. As a liquid raw material (L) for forming an interlayer insulating film of a VLSI by the CVD method (chemical vapor deposition method), TEOS (Tet
ra Ethyl Ortho Silicate) is widely used.
The reason is that C using conventional monosilane gas is used.
The step coverage (coverage of the step) is better than that of the film formed by the VD method, and monosilane gas is extremely reactive and may cause an explosion accident, while TEOS is highly safe. , Easy to save,
This is because it has many merits such as high purity and low cost expected as raw materials in the future.

Now, FIG. 5 is an example of a schematic configuration diagram of a semiconductor manufacturing process apparatus using a liquid vaporization feeder (LMFC). In this process equipment, a liquid raw material tank (T), a liquid vaporizer (LMFC), and a cylinder storing a carrier gas (H) are stored.
(Not shown) and reaction chamber (B). The liquid raw material tank (T) stores the liquid raw material (L) in an airtight manner,
Pressurize the liquid raw material tank (T) with an inert gas (F) to feed the liquid raw material (L) to the liquid vaporizer (LMFC) through the liquid supply pipe (LP) inserted in the liquid raw material (L). It is supposed to be supplied.

In FIGS. 6 and 7 which are conventional examples, a liquid vaporization feeder (LMFC) is composed of a flow rate measuring unit (LM) and a vaporization feeding unit (VS), and the flow rate measuring unit (LM) is , A sensor tube (1) that accurately detects the flow rate of the liquid raw material (L) passing through, and a sensor tube
In principle, it is composed of a bypass pipe (2) through which the liquid raw material (L) flows in direct proportion to the flow rate of (1). The vaporization supply unit (VS)
A flow rate control valve (7) for accurately controlling the flow rate of the liquid raw material (L) flowing through the sensor pipe (1) and the bypass pipe (2) into the flow control chamber (6), and the liquid raw material (L) A vaporizer opening / closing valve that opens and closes the vaporization chamber (13) that vaporizes and evaporates the liquid and supplies it to the reaction chamber (B) together with the carrier gas (H), and the liquid junction (23) for the exudation of the liquid raw material (L).
(12) consists of and the entire vaporization supply unit (VS) is a thermostatic chamber.
It is stored in (A1). Flow rate measurement unit (LM) and vaporization supply unit
(VS) is connected by a joint (26), and the combined liquid raw materials (L) are sent to the flow rate control chamber (6).

Flow control valve (7) and vaporizing on-off valve (12)
Is the housing block (11), as can be seen in Figs.
It is housed and integrated in the inside, and the vaporizing on-off valve (12) is arranged on the upper side and the flow control valve (7) is arranged on the lower side. The flow control chamber (6) of the flow control valve (7) and the vaporization chamber (1) on the vaporization on-off valve (12) side
3) means the liquid junction (2
It is connected in 3). Further, in FIG. 7, a carrier gas inflow path (14) and a mixed gas outflow path (15) are connected to the vaporization chamber (13), and a carrier gas cylinder (not shown) is connected to the carrier gas inflow path (14). However, the mixed gas outflow passage (15) has a reaction chamber in the next step.
(B) is connected.

The control valve body (8) of the flow control valve (7) is housed in the flow control chamber (6), and the opening degree of the inlet of the liquid junction (23) is controlled by the control valve body (8). Is precisely controlled by the flow rate control actuator (17) to accurately control the supply amount of the liquid raw material (L) flowing into the flow rate control chamber (6) from the liquid inflow passageway (5) to the vaporization chamber (13). .

The carburetor on-off valve (12) is composed of an on-off actuator (25) and a valve body (3) installed in the center of the lower surface of the carburetor on-off valve (12). The liquid outlet of the junction (23) to the vaporization chamber (13) is opened and closed. The reaction chamber (B) connected to the mixed gas outflow passage (15) is
For example, it is a reaction chamber of a semiconductor manufacturing apparatus such as a CVD apparatus.

Thus, an inert gas such as helium or nitrogen
(F) pressurizes the raw material tank (T), and the liquid raw material inside
Supply (L) to the liquid vaporizer (LMFC). In the liquid vaporizer (LMFC), the flow control valve (7) is used as detailed above.
By this control action, a certain amount of liquid raw material (L) is supplied to the vaporization chamber (13).

When the liquid raw material (L) is supplied into the flow rate control chamber (6), the tip of the liquid raw material (L) is exposed from the liquid outlet through the liquid junction (23). At this time, by controlling the opening degree of the control valve body (8), the amount of the liquid raw material (L) flowing into the liquid junction (23) from the inlet of the liquid junction (23) is controlled by the flow rate measurement unit (LM). While flowing into the liquid junction portion (23) while being controlled to a set value by a signal from, the liquid outlet overflows into the vaporization chamber (13). Constant temperature bath (A1)
Since the inside is heated to a constant temperature, the effluent liquid raw material
(L) evaporates and evaporates in the exposed area. On the other hand, a carrier gas (H) such as helium is supplied from the carrier gas inflow path (14) of the vaporizer opening / closing valve (12), and becomes a mixed gas (Kn) by mixing with the vaporized raw material gas, Mixed gas outlet
It flows out from (15) and is supplied to the reaction chamber (B) while being heated to a predetermined temperature by a pipe heater (not shown).

A mixed gas of carrier gas (H) and raw material gas
On the side of the reaction chamber (B) receiving the supply of (Kn), the mixed gas (K
There is a change in the required amount of n), and the liquid vaporization supply device (LMFC) must supply the required amount accurately and stably in accordance with the request of the reaction chamber (B) side. Well, liquid raw material
When the flow rate of (L) is relatively low (this point will be described in detail in the comparative example of the present invention and the conventional example), the flow rate of the carrier gas (H) is sufficient to vaporize the liquid raw material (L). If it is, stable vaporization is possible.
The flow rate of carrier gas (H) is insufficient with respect to the supply amount of (L), and some of the liquid raw material (L) that was not vaporized due to the lack of the heat supply required for vaporization is used directly in the downstream piping. Flow into the raw material, and the amount of raw material gas fluctuates due to the following reasons, resulting in variations in the thickness of the film formed on the semiconductor wafer,
There was a risk of adverse effects such as defective products.

This point will be described in detail with reference to FIG. Liquid raw material
When the flow rate of (L) increases, the partial pressure of the vaporized raw material gas in the atmosphere near the liquid outlet (23a) becomes saturated, and all the liquid raw material (L) supplied cannot be vaporized, and the liquid outlet Liquid raw material (L) collects around (23a) and starts to bump. Liquid raw material to be vaporized
When (L) scatters into droplets due to bumping, the droplet portions are not immediately vaporized, so that the concentration of the source gas is temporarily reduced and at the same time the pressure in the vaporization chamber (13) is greatly reduced. Liquid droplets of the liquid raw material (L) scattered by bumping are then collected from the bottom of the valve body (3) of the vaporizer on-off valve (12) and the vaporization chamber (1
3) It adheres to the inner wall inside. Then, the adhered droplets evaporate rapidly to increase the pressure in the vaporization chamber (13).

When the supply amount of the liquid raw material (L) is excessive with respect to the flow rate of the carrier gas (H) as described above, {burst boiling ■ scattering of liquid raw material ■ evaporation of scattered droplets ■ bumping} is repeated. As a result, the pressure in the vaporization chamber (13) fluctuates greatly. At the same time, the rise in pressure in the vaporization chamber (13) causes a reduction in the vaporization rate, which hinders the smooth vaporization of the liquid raw material (L). Further, the pressure fluctuation causes the pressure fluctuation in the reaction chamber (B), and the fluctuation of the concentration of the raw material gas caused by the fluctuation causes the thickness of the film on the semiconductor wafer to vary, Due to the scattering and adhesion, a spot (spot) is generated on the wafer surface, which is a major cause of wafer defects.

By vaporization of the unstable liquid raw material (L). The pressure in the reaction chamber (B) fluctuates, which causes instability of plasma, which is a major cause of increasing the defective rate of semiconductor products.

[0014]

The first object of the present invention is to enable stable vaporization of the supplied liquid raw material even when the supply amount of the liquid raw material increases, in vaporizing and evaporating the supplied liquid raw material. Secondly, stable vaporization is ensured to ensure stable operation of the semiconductor manufacturing apparatus, reduce the defective rate of semiconductor products, and improve the yield.

[0015]

The method for vaporizing and supplying a liquid raw material according to the present invention is to supply a constant flow rate of a liquid raw material (L) to a vaporization chamber (13) and to supply a carrier gas (H) to the vaporization chamber (13). Then, the liquid raw material (L) that has exuded into the vaporization chamber (13) is evaporated and vaporized, and a mixed gas (Kn) of the carrier gas (H) and the vaporized raw material gas is supplied to the reaction chamber (B). In the vaporization and supply method for liquid raw materials, the carrier gas (H) is sprayed at a high speed toward the liquid outlet (23a) from which the liquid raw material (L) exudes, and the carrier gas (H) in the vicinity of the liquid outlet (23a) is discharged. It is characterized in that the evaporation / vaporization of the liquid raw material (L) is promoted by increasing the flow velocity and reducing the pressure in the vicinity of the liquid outlet (23a).

The carrier gas (H) is ejected toward the liquid outlet (23a). As a result, the vaporized source gas is removed from the space near the liquid outlet (23a), the partial pressure of the source gas is reduced, and the vaporization of the liquid source (L) is significantly promoted. The vaporized raw material gas is uniformly mixed with the carrier gas (H) to form a mixed gas (Kn), and the mixed gas outflow path (15)
And is supplied to the reaction chamber (B).

Claim 2 is a first for carrying out the method.
In the embodiment, the liquid outlet (23a) for supplying the liquid raw material (L) to the vaporization chamber (13)
And a vaporization chamber that evaporates and vaporizes the supplied liquid raw material (L)
(13), a carrier gas injection nozzle (4) for injecting the carrier gas (H) into the liquid outlet (23a) opening to the vaporization chamber (13), and the vaporized source gas and carrier gas (H) in the vaporization chamber. It is characterized in that it is composed of a mixed gas discharge port (15a) supplied from (13) to the reaction chamber (B). Here, the carrier gas (H) is ejected from the carrier gas injection nozzle (4).
Will be done by.

Claim 3 is a second for carrying out the method.
In the embodiment, the liquid outlet (23a) for supplying the liquid raw material (L) to the vaporization chamber (13)
And a vaporization chamber that evaporates and vaporizes the supplied liquid raw material (L)
(13), a carrier gas supply port (14a) for supplying the carrier gas (H) to the vaporization chamber (13), and a gap (S) between the liquid outlet (23a) and the liquid outlet (23a). ) To increase the flow rate of the carrier gas (H) on the liquid outlet (23a) and the vaporized source gas and carrier gas (H) from the vaporization chamber (13) to the reaction chamber (B). And a mixed gas discharge port (15a) for supplying to Here, the gap (S) is limited by the diaphragm (4A), and the flow velocity of the carrier gas (H) is increased.

A fourth aspect of the present invention is limited to the second and third aspects, in which the liquid outlet (23a) is provided with a liquid junction insertion protrusion (9) slightly thinner than the liquid outlet (23a). Fine gap (10) for exuding the liquid material between the inner circumference of 23a) and the outer circumference of the liquid junction insertion protrusion (9)
And a rod heater (22) is installed near the liquid outlet (23a). As a result, the volume of the liquid raw material (L) that exudes through the fine gap (10) to the liquid outlet (23a) becomes extremely small, and therefore,
The heating by the heater (22) is easy, uniform and sufficient. As a result, the rapid vaporization of the liquid raw material (L) can be achieved even when the flow rate increases in combination with the ejection of the carrier gas (H). In addition to this, effective heat supply is performed against the ambient temperature drop that occurs when the liquid raw material (L) is vaporized, preventing the ambient temperature from dropping, and
Promotes vaporization of (L).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a vaporization supply section (VS) of a liquid vaporization feeder (LMFC), and FIG. 1 shows a half sectional view of the first embodiment. The schematic configuration diagram of the present invention is as shown in FIG. Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
In the vaporization supply unit (VS) of FIG. 1, the housing block (1
The opening / closing actuator (25) is installed on the upper surface of (1), and the flow control actuator (17) is installed on the lower surface via the flow control chamber closing flange (16). The housing block (11) is provided with a mounting hole (18) opening on the upper surface and is mounted with a mounting portion for the opening / closing actuator (25), and the carburetor connected to the opening / closing actuator (25). The valve body (3) of the on-off valve (12) is inserted. Mounting hole (18)
The bottom part of the is a vaporization chamber (13), and the carrier gas inflow path
The (14) and the mixed gas outflow passage (15) are connected to each other, and the carrier gas supply port (14a) and the mixed gas discharge port (15a) thereof are opened to the vaporization chamber (13), respectively. The opening / closing actuator (25) is composed of, for example, a pneumatic actuator. On the other hand, the flow rate control actuator (17) is composed of, for example, a laminated piezoelectric element, an electromagnetic solenoid, or the like.

Below the vaporization chamber (13), a flow rate control chamber (6) that opens to the lower surface of the housing block (11) is provided. The flow rate control chamber (6) and the vaporization chamber (13) are separated from each other. The liquid junction (23) provided in the partition (19) communicates with each other. A flow control chamber closing flange (16) having a control diaphragm (20) is fixed to the lower surface of the housing block (11) in a liquid-tight state. The control valve body (8) is housed in the flow rate control chamber (6),
The liquid junction insertion protrusion (9) protruding from the upper end of the liquid junction (23)
And a fine gap (10) is formed between the inner periphery of the liquid junction (23) and the outer periphery of the liquid junction insertion protrusion (9). Control valve
A projection (8a) is provided on the lower surface of the (8) and is in contact with the control diaphragm (20).

The upper half of the side surface of the control valve body (8) is formed to have a small diameter, and the coil spring (21) is inserted in the small diameter portion, so that the control valve body (8) is controlled by the control diaphragm (20). It is biased to the side. On the upper surface of the control valve body (8), the liquid junction insertion protrusion (9)
A ring-shaped seal projection (8a) is provided so as to surround the periphery of the partition wall (9a) so as to come into contact with and separate from the lower surface of the partition wall (19). Plunger for flow control actuator (17)
(17a) is in contact with the lower surface of the control diaphragm (20), and drives the control valve body (8) via the control diaphragm (20).

A rod heater (22) and a temperature sensor (24) are embedded in the partition wall (19) in the vicinity of the liquid junction (23).
9) The temperature of the part is kept constant and the liquid raw material (L) is heated. The flow rate measurement unit (LM) and vaporization supply unit (VS) are connected via the liquid inlet joint (5a),
(L) flows into the flow control chamber (6). In the carrier gas inflow path (14), a carrier gas injection nozzle (4) having a squeezed tip and a tip directed toward the liquid outlet (23a) is arranged. The bending angle of the tip portion is indicated by (θ).
(FIGS. 2 and 4) As the carrier gas (H), for example, helium simple substance or a mixed gas of other gases is used.

As described above, the inert gas (F) such as helium or nitrogen is supplied to the upper space of the raw material tank (T) to increase the atmospheric pressure in the raw material tank (T) to increase the internal liquid raw material ( L) is supplied to the liquid vaporizer (LMFC). Liquid vaporizer (LMF
In the flow rate measuring unit (LM) of C), the liquid raw material (L) flows into the sensor pipe (1) and the bypass pipe (2) in a branched manner, and by measuring the flow rate of the sensor pipe (1), the bypass pipe (2) It is possible to measure the total flow rate including). Liquid raw material (L) exiting the flow rate measuring unit (LM)
Enters the flow rate control chamber (6) through the liquid inflow passage (5), passes between the control valve body (8) and the partition wall (19), and enters the fine gap (10) of the liquid junction (23). , And oozes out to the liquid outlet (23a) opening in the vaporization chamber (13) due to the capillary phenomenon.

The outflow amount of the exuding liquid raw material (L) is controlled by the control valve body.
It is determined by the opening of (8), and the opening is controlled by the flow control actuator (17). When closed, the carburetor open / close valve (1
2) is operated to close the liquid outlet (23a).

The carrier gas (H) is ejected toward the liquid outlet (23a) through the carrier gas injection nozzle (4), whereby the vaporized raw material gas is taken from the space near the liquid outlet (23a). The partial pressure of the raw material gas is reduced, and as a result, the liquid raw material (L) is significantly promoted.

At the same time, the liquid raw material (L) exuding to the liquid outlet (23a) through the fine gap (10) of the liquid junction (23) is heated by the rod heater (22), Since it is inserted in the liquid junction insertion protrusion (9) in (23), heat can be easily transferred to the liquid raw material (L) that passes through the fine gap (10), and therefore it can be heated evenly and sufficiently. Even when the flow rate of the liquid raw material (L) is increased by being exuded to the liquid outlet (23a) and jetted of the carrier gas (H), the rapid vaporization of the liquid raw material (L) is achieved.

Further, when the liquid raw material (L) is vaporized, a partition wall
(19) The heat of vaporization is taken from the ambient atmosphere and its surroundings, and the temperature tends to decrease (the temperature decrease hinders vaporization of the liquid raw material (L)), but the heat is rapidly supplied by the rod heater (22), The partition wall (19) and the ambient temperature are prevented from lowering to promote vaporization of the liquid raw material (L). The vaporized raw material gas is uniformly mixed with a carrier gas (H) such as helium to form a mixed gas (Kn), which flows out of the mixed gas outflow passage (15) and is supplied to the reaction chamber (B).

FIG. 3 shows an example in which a diaphragm (4A) is used instead of the carrier gas injection nozzle (4), and the diaphragm (4A) is arranged so as to enclose the lower surface of the valve body (3). By raising and lowering, the gap (S) between the diaphragm (4A) and the liquid outlet (23a) is defined. The carrier gas (H) flowing into the gap (S) increases its flow velocity when passing through the narrow gap (S), and the carrier gas injection nozzle
It has the same effect as (4).

(Experimental example) As the carrier gas ejection nozzle (4),
A capillary tube having an inner diameter of 0.5 mm and a length of 20 mm was used, and it was bent so that its tip end faced the liquid outlet (23a). Liquid raw material used
(L) is TEOS (Tetra Ethyl Ortho Silicate), which is 0.2 g / min, 0.4 g / min, 0.6 g as shown in FIGS.
The experiment was carried out by dividing into 5 stages of / min, 0.8 g / min, and 1.0 g / min. Nitrogen gas was used as the carrier gas (H), and the flow rate was 1 liter / min. The temperature in the constant temperature layer (A1) is 90 ~
It was set to 100 ° C. According to this, in the conventional device,
As shown in FIG. 10, the pressure fluctuation on the side of the mixed gas discharge passage (15) does not occur at the stage of 0.2 g / min, but at 0.4 g / min, a slight pressure fluctuation is observed, and gradually increases and becomes 1 At 0.0 g / min, pressure fluctuations occurred to an unusable degree. On the other hand, in the present invention, as shown in FIG. 9, 0.2 g / min, 0.4 g / min,
Good results were obtained with no pressure fluctuations in all of the five stages of 0.6 g / min, 0.8 g / min, and 1.0 g / min.

[0031]

According to the present invention, since the carrier gas is jetted toward the liquid outlet, the vaporized raw material gas is removed from the space near the liquid outlet, and the partial pressure of the raw material gas is reduced. The vaporization of the liquid raw material is significantly promoted, and as a result, the liquid raw material can be vaporized and evaporated smoothly even if the supply amount of the liquid raw material is increased. Furthermore, since the liquid raw material passes through the minute gaps, the liquid can be rapidly and sufficiently heated, and the rapid vaporization of the liquid raw material can be achieved even when the flow rate is increased in combination with the jet of the carrier gas. .

[Brief description of drawings]

FIG. 1 is a half cross-sectional view of a vaporization supply section of a liquid source vaporization supply device of the present invention.

FIG. 2 is a partially enlarged sectional view of a vaporization chamber portion of FIG.

FIG. 3 is a partially enlarged cross-sectional view of another embodiment of the vaporization chamber portion of the present invention.

FIG. 4 is a partially enlarged view showing a relationship between a carrier gas injection nozzle and a liquid outlet portion of the present invention.

FIG. 5 is a schematic configuration diagram when a vaporizer for liquid raw material is used.

FIG. 6 is a sectional view of a conventional vaporizer for liquid raw materials.

7 is a sectional view taken along line XX of FIG.

FIG. 8 is an enlarged sectional view of an essential part showing a bumping state in a conventional example.

FIG. 9 is a pressure fluctuation graph of the reaction chamber during vaporization by the vaporizer for liquid raw material of the present invention.

FIG. 10 is a graph showing pressure fluctuations in the reaction chamber during vaporization by the vaporizer for liquid raw material of the conventional example.

[Explanation of symbols]

 (13) ... Vaporization chamber (23a) ... Liquid outlet (L) ... Liquid raw material (LMFC) ... Liquid raw material vaporizer (H) ... Carrier gas

Claims (4)

[Claims] 1. A liquid raw material whose flow rate is controlled is supplied to a vaporization chamber and a carrier gas is supplied to the vaporization chamber to vaporize and vaporize the liquid raw material that has exuded into the vaporization chamber, and vaporize the carrier gas. In the vaporization and supply method for a liquid raw material that supplies a mixed gas of raw material gases to the reaction chamber, by blowing the carrier gas at a high speed toward the liquid outlet from which the liquid raw material seeps out, and increasing the flow velocity of the carrier gas near the liquid outlet. A vaporization and supply method for a liquid raw material, which is characterized by promoting evaporation and vaporization of the liquid raw material. 2. A liquid outlet for supplying a liquid raw material whose flow rate is controlled to a vaporization chamber, a vaporization chamber for evaporating and vaporizing the supplied liquid raw material, and a carrier gas for injecting a carrier gas to a liquid outlet opened to the vaporization chamber. A vaporizer for a liquid raw material, comprising an injection nozzle and a mixed gas discharge port for supplying a vaporized raw material gas and a carrier gas from a vaporization chamber to a reaction chamber. 3. A liquid outlet for supplying a liquid raw material whose flow rate is controlled to a vaporization chamber, a vaporization chamber for evaporating and vaporizing the supplied liquid raw material, a carrier gas supply port for feeding a carrier gas to the vaporization chamber, A diaphragm that increases the flow velocity of the carrier gas above the liquid outlet by limiting the gap between the liquid outlet and the liquid outlet, and the mixed gas exhaust that supplies the vaporized source gas and carrier gas from the vaporization chamber to the reaction chamber. A vaporizer for liquid raw materials, characterized in that it is configured with an outlet. 4. A liquid junction insertion protrusion slightly thinner than the liquid outlet is provided in the liquid outlet to form a gap for exuding the liquid raw material between the inner periphery of the liquid outlet and the outer periphery of the liquid junction insertion protrusion. The liquid source vaporizer according to claim 2 or 3, wherein a heater is installed near the liquid outlet.