JP3101029B2 - Liquid material feeder for vaporization - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-precision supply of a liquid raw material in a semiconductor manufacturing process, and more particularly to a method of supplying a TEOS (Tetra
Ethyl Ortho Silicate) and other high-precision flow control of thin film forming liquid raw materials
The present invention relates to improvement of a liquid material supply device for vaporization which is most suitable for high-precision transfer of (for example, alcohols and organic acids), particularly for a high-precision transfer in a reactor or the like in which the next step is in a reduced pressure state.

[0002]

2. Description of the Related Art Hereinafter, a CVD process for manufacturing a semiconductor will be described as an example. As an interlayer insulating film material for semiconductor wafers, TEOS has recently been receiving particular attention as a liquid material for vaporization. The reason for this is that, unlike the deposition mechanism of (SiH ₄ ) using conventional low-pressure CVD, the surface reaction is rate-determining, so that step coverage is good, and SiH ₄ is extremely reactive, causing an explosion accident. On the other hand, TEOS is highly safe and easy to store, and is expected to reduce costs as a raw material in the future.

[0003] When such a liquid raw material is used, there are the following serious problems. That is, a certain amount of gas is dissolved in the liquid raw material due to its properties. The amount of dissolved gas depends on the type, temperature, and pressure applied to the liquid material. When the flow rate of the liquid raw material is controlled by the liquid raw material supply device for vaporization, the dissolved gas is bubbled due to a minute temperature change or pressure change while the liquid raw material flows through the flow path in the liquid raw material supply device for vaporization, Mixed into liquid raw materials.

[0004] When such bubbles flow together with the liquid raw material, no serious problem is caused. However, if the bubbles are caught in the flow path and hinder the flow of the liquid raw material, a serious problem will be caused. That is, when air bubbles are caught on the sensor tube, the liquid material stops flowing into the sensor tube,
Although the liquid raw material continues to flow through the bypass pipe, the flow rate of the output signal from the sensor unit becomes zero.

[0005] Further, if the bubbles accumulate and become large bubbles, the liquid raw material supplied to the next step is interrupted by the amount of the bubbles, and the flow rate control becomes unstable.

[0006]

An object of the present invention is to provide a TE
When supplying a liquid material such as an OS, even if bubbles are generated in the liquid material, the bubbles easily escape to the material tank side, and are not caught in the middle of the flow path, and the bubbles do not accumulate to become large bubbles. It is to supply in this way.

[0007]

According to a first aspect of the present invention, there is provided a liquid material supply device for vaporization (A) comprising a capillary tube and a liquid material (L) flowing through the inside thereof. ), A sensor pipe (1) for measuring the mass flow rate, a bypass pipe (2) through which the liquid raw material (L) can flow in proportion to the liquid raw material (L) flowing through the sensor pipe (1), and the sensor From pipe (1) or sensor pipe (1) and bypass pipe
And a flow control valve (3) for controlling the supply amount of the liquid raw material (L) flowing out from (2), the liquid provided in the supply (A) in the liquid raw material supply device (A) for vaporization. In the flow path of the raw material (L),
The horizontal flow path (H) is characterized in that the horizontal flow path (H) is formed so as to be inclined downward so that the liquid material inflow side of the horizontal flow path (H) is higher than the outflow side.

Accordingly, in the horizontal flow path (H), the bubbles (13) rise against the flow of the liquid raw material (L), and do not stay in the horizontal flow path (H). There is no interruption of the liquid raw material (L) due to the accumulation of (13).

In the bypass portion, a sensor tube (1) for measuring a mass flow rate of the liquid raw material (L) flowing through the inside of the sensor tube (1) is constituted by a capillary tube. A bypass pipe (2) through which the liquid raw material (L) can flow in proportion to the liquid raw material (L) flowing through the sensor pipe (1) or from the sensor pipe (1) and the bypass pipe
In the vaporizing liquid material supply device (A) composed of a flow control valve (3) for controlling the supply amount of the liquid material (L) flowing out from (2), the flow path of the bypass pipe (2) is vertical. The bypass pipe (2) is placed in the bypass pipe storage hole (4) so that the liquid material inflows into the ceiling surface (5) of the bypass pipe storage hole (4).
(6) is provided, and the ceiling surface (5) is formed so as to be inclined upward toward the liquid material inlet (6).

As a result, air bubbles generated in the bypass portion
(13) rises without stagnation in the bypass pipe (2), and flows into the liquid material inlet (6) along the ceiling surface (5) formed on the ascending slope, and the bypass pipe housing hole (4 Bubbles inside
(13) does not stay.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a cross-sectional view of the vaporizing liquid raw material supplier (A), and FIG. 2 is a plan view of the vaporizing liquid raw material supplier (A). In FIG. 1, (A) is a liquid material supply device for vaporization, (T) is a material tank, and the liquid material supply device for vaporization (A) is disposed immediately below the material tank (T). The vertical feed pipe (7) provided at the bottom of (T) and the raw material receiving pipe (8) provided on the upper surface of the vaporizing liquid raw material feeder (A) are connected, and the liquid raw material in the raw material tank (T) is connected. (L) is supplied to the vaporizing liquid raw material supply device (A).

In the figure, (1) is a sensor tube which is formed of an extremely thin capillary and is horizontally arranged at the lowermost part of the body (9), and its upstream side is connected to the raw material receiving pipe (8). It is connected to a sensor section upstream connection pipe (11) branched from the main vertical flow path (10) communicating therewith, and the downstream side thereof is downstream of the sensor section communicating with the junction bottom (12) of the bypass pipe housing hole (4). The liquid source (L) flows in the direction of the solid line arrow, and the bubbles (13) flow in the direction of the broken line arrow. (Ru) and (Rd) are thermal sensors, which are respectively provided at two appropriately separated points of the sensor tube (1). Ambient temperature sensing resistor (R t u) (R t d) is disposed through the heat sink (14) is in its lower. The horizontal flow path (H) of the sensor section upstream connection pipe (11) has a horizontal flow path (H) formed so as to be inclined downward so that the liquid raw material inflow side is higher than the outflow side. The bubbles (13) generated in the pipe (11) rise and rise in the main vertical flow path (1) without staying in the horizontal flow path (H).
0).

The bypass pipe (2) is capable of flowing a large amount of the liquid raw material (L) in proportion to the liquid raw material (L) flowing through the sensor pipe (1). The bypass holes are accommodated in the vertical direction, and the bypass holes are arranged in the vertical direction. The ceiling surface (5) of the bypass pipe housing hole (4) communicates with the main vertical flow path (10), and the ceiling surface (5) is connected to the liquid material inlet (6) formed on the ceiling surface (5). ), And the air bubbles (13) generated in the bypass section rise without stagnation in the ceiling and flow into the raw material tank (T) through the main vertical flow path (10). I have to do it.

The lower part of the bypass pipe housing hole (4) is a bypass pipe.
The outlet of (2) and the sensor section downstream connecting pipe (15) communicating with the outlet of the sensor pipe are the merging bottom (12) where they merge,
The merging bottom (12) and the valve chamber (18) on the side of the flow control valve (3) communicate with a merging horizontal flow path (H ₁ ), which is one of the horizontal flow paths.

The flow control valve (3) is connected to the housing block (1).
6) It is stored horizontally inside, and the valve opening is precisely controlled by an actuator (17) such as a piezo actuator or a solenoid actuator, and from the junction bottom (12) to the valve chamber (18). The supply amount of the inflowing liquid raw material (L) to a vaporizer (not shown) is accurately controlled.

The supply flow path (19) led out of the valve chamber (18) exits to the side of the vaporizing liquid raw material supply device (A) as shown in FIG.
Connected to liquid source vaporizer. The liquid source vaporizer is connected to a reaction furnace (not shown), for example, a semiconductor manufacturing apparatus such as a CVD apparatus, so that the source gas vaporized by the carrier gas in the liquid source vaporizer is supplied. ing.

The raw material tank (T) is connected to a pressurized gas source (20), and the gas pressure in the raw material tank (T) is adjusted by a pressure regulator (22) while watching a pressure gauge (21). I have.

Thus, an inert gas such as helium or nitrogen is supplied to the upper space of the raw material tank (T) to increase the pressure in the raw material tank (T), and the liquid raw material (L) in the raw material tank (T) is increased. ) Is supplied to the liquid material supply device for vaporization (A). Then vertical supply pipe (7),
The liquid raw material (L) flows down through the raw material receiving pipe (8) and flows into the main vertical flow path (10). Liquid raw material that has flowed into the main vertical flow path (10)
A part of (L) branches and passes through the sensor part upstream connection pipe (11), the sensor pipe (1), the sensor part downstream connection pipe (15), and joins the bottom part.
(12), while the liquid raw material enters the main vertical channel (10)
Most of (L) enters the junction bottom (12) through the bypass pipe (2) and enters the valve chamber (18) through the junction horizontal flow path (H).

The arithmetic unit (23) calculates the mass flow rate of the liquid raw material (L) flowing through the sensor tube (1), determines the valve opening of the flow control valve (3), and sets the actuator (17) Operate. Thereby, the liquid material (L) having a preset mass flow rate flows out of the valve chamber (18) to the supply flow path (19), and the liquid material vaporizer
(Not shown). The liquid raw material (L) flowing into the liquid raw material vaporizer (not shown) is contacted with the carrier gas and vaporized,
It is supplied to a reaction furnace and the like.

As described above, the liquid raw material (L) is strictly controlled and supplied to a liquid raw material vaporizer (not shown). There are various flow conditions, such as vertical, horizontal or thick parts, movable parts such as valves, and parts to which heat is applied, and the conditions applied to the liquid raw material (L) in the flow path are different. In addition, the dissolved gas may be bubbled. The bubbles (13) rise because they have a lower specific gravity than the liquid raw material (L), but rise in the vertical channel without being caught. In the horizontal flow path (H), the liquid material inflow side is formed so as to be inclined downward so as to be higher than the outflow side, so that the bubbles (13) move to the side opposite to the flow direction of the liquid material (L), Does not stay in the horizontal flow path (H).

Air bubbles also occur in the bypass pipe housing hole (4). However, since the bypass pipe (2) is installed vertically, the air bubbles (13) generated in the bypass hole rise and rise to the bypass pipe ( 2) Do not stay inside. And the rising bubble (13)
Rises along the ceiling surface (5) formed so as to be inclined upward toward the liquid material inlet (6), and the main vertical flow path (1
It flows into 0) and goes out to the raw material tank (T).

Also, there is a possibility that air bubbles may occur in the downstream connection pipe (15) of the sensor part, and air bubbles may also occur in the valve chamber (18). Rises into the junction bottom (12), then rises through the bypass pipe (2), and flows into the raw material tank (T) through the same path as described above.

In this manner, the bubbles (1
3) are all raised and returned to the raw material tank (T), and are caught in the middle of the flow path, obstructing the flow of the liquid raw material (L) or accumulating to form large bubbles (13) to form the liquid raw material (L). ) Supply is not interrupted.

[0024]

According to the present invention, there is provided a liquid material supply device for vaporization according to the present invention, wherein the liquid material flows out of the liquid material inflow side of the horizontal flow passage among the liquid material flow passages provided in the supply device. Since the horizontal flow path is formed so as to be lower than the side, the bubbles generated in the vertical flow path as well as the bubbles generated in the horizontal flow path all rise and return to the raw material tank, There is an advantage that the flow of the liquid raw material is not hindered by being caught in the middle of the process, and the supply of the liquid raw material is not interrupted due to accumulation of large bubbles.

In the present invention, the bypass pipe is arranged in the bypass pipe receiving hole such that the flow path of the bypass pipe is vertical, and the liquid material inlet is provided on the ceiling surface of the bypass pipe receiving hole. In addition, since the ceiling surface is formed so as to be inclined upward toward the liquid raw material inlet, all the bubbles generated in the bypass pipe also rise, and furthermore, the bubbles are formed along the ceiling surface formed with the upward inclination. Rises and flows into the liquid material inlet,
There is no such thing as bubbles staying in the bypass pipe storage hole, and there is no hindrance to the flow of the liquid material here, and there is no interruption of the supply of the liquid material by forming large bubbles by accumulation. There are advantages.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a liquid material supply device for vaporization of the present invention.

FIG. 2 is a plan view of a liquid material supply device for vaporization of the present invention.

[Explanation of symbols]

(A) Liquid material feeder for vaporization (L) Liquid material (H) Horizontal flow path (1) Sensor pipe (2) Bypass pipe (3) Flow control valve (4) Bypass pipe storage hole (5)… Ceiling surface (6)… Liquid material inlet (13)… Bubbles

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C23C 16/00-16/56 B01D 19/00 G01F 1/00-9/02 G05D 7/00-7 / 06 H01L 21/205

Claims (2)

(57) [Claims] A sensor tube configured by a capillary tube for measuring a mass flow rate of a liquid material flowing through the sensor tube; a bypass tube capable of flowing the liquid material in proportion to the liquid material flowing through the sensor tube; Alternatively, in a liquid material supply device for vaporization constituted by a sensor pipe and a flow rate control valve for controlling a supply amount of the liquid material flowing out from the bypass pipe, a horizontal flow path is provided in a liquid material flow path provided in the supply apparatus. A horizontal flow path is formed so as to be inclined downward so that the inflow side of the liquid material is higher than the outflow side. 2. A sensor tube configured by a capillary tube for measuring a mass flow rate of a liquid material flowing through the sensor tube; a bypass tube capable of flowing the liquid material in proportion to the liquid material flowing through the sensor tube; Alternatively, in a vaporizing liquid material supply device composed of a sensor pipe and a flow rate control valve for controlling a supply amount of liquid material flowing out of the bypass pipe, the bypass pipe is connected so that the flow path of the bypass pipe is vertical. A liquid for vaporization characterized by being disposed in a storage hole, providing a liquid material inlet at a ceiling surface of the bypass pipe storage hole, and forming a ceiling surface so as to be inclined upward toward the liquid material inlet. Raw material feeder.