JPH11131237A - Method and device for supplying source gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily supply a source gas in a stable quantity. SOLUTION: In a method to supply the source gas generated through the bubbling of a liquid source, a set value of the supply of the source gas is first obtained in a first step S1. In a second step S2, the liquid source is bubbled by supplying an inert gas to generate the source gas. In a third step S3, the supply of the generated source gas is measured to obtain a measured value. In a fourth step S4, the measured value is judged whether or not it is within a prescribed range of the set value, and when it is judged NO, the process is advanced to a fifth step S5, or when it is judged YES, the process is advanced to a sixth step S6. In the fifth step S5, the supply of the inert gas is regulated so that the measured value is brought close to the set value, and the process is returned to the third step S3. In the sixth step S6, the supply of the inert gas is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for supplying a source gas into a reaction chamber in, for example, a film forming step in the manufacture of a semiconductor device.

[0002]

2. Description of the Related Art CVD (Chemic) in semiconductor device manufacturing.
In the hal Vapor Deposition (chemical vapor deposition method)) step, the liquid source may be gasified by bubbling with an inert gas, and this gas may be supplied into the reaction chamber as a source gas (deposition gas). In this case, a predetermined amount of source gas is supplied into the reaction chamber by one of the following two methods.

Prior to the above manufacturing process, data on the supply amount of the source gas with respect to the supply amount of the inert gas used for bubbling is obtained. Then, from this data and the set value of the supply amount of the source gas in the above manufacturing process,
The supply amount of the inert gas required in the above manufacturing process is obtained. Next, bubbling of the liquid source is performed by controlling the supply amount of the inert gas so that a certain amount of the obtained inert gas is supplied into the liquid source. This method is called an open loop method. When controlling the supply amount of the source gas in this manner, an open-loop source gas supply device provided with a flow controller (that is, a mass flow controller) for controlling the supply amount of the inert gas is used. FIG. 4 shows the change over time in the amount of source gas generated by the open loop method. In the supply method of the open loop system, as shown in this graph, it can be seen that the supply amount of the source gas is stabilized around the set value after a predetermined time has elapsed since the start of the flow of the inert gas.

A source gas is generated by bubbling a liquid source with an inert gas, and a supply amount of the source gas into a reaction chamber is measured. The supply amount of the inert gas is adjusted so that the measured value becomes closer to the set value. During the manufacturing process, the measurement of the supply effort of the source gas and the adjustment of the inert gas supply rate are repeated so that the supply rate of the source gas into the reaction chamber becomes closer to the set value. This method is called a closed loop method. When controlling the supply amount of the source gas in this manner, a flow controller that controls the supply amount of the inert gas, a flow measurement device that measures the supply amount of the source gas (that is, a mass flow meter),
A closed-loop source gas supply device provided with a control circuit for controlling the flow controller so that the value measured by the flow meter approaches a set value is used.

[0005]

However, the above-described method and apparatus for supplying a source gas have the following problems.
In other words, in the open-loop source gas supply method and apparatus, it is necessary to obtain data on the supply amount of the source gas with respect to the supply amount of the inert gas before performing the processing step using the source gas. For this reason,
The above processing steps are troublesome. FIG. 5 shows the change over time of the supply amount of the source gas by the closed loop method. As shown in this figure, in the closed-loop source gas supply method, the supply amount of the source gas approaches the set value based on the measured value fed back, so that the supply amount of the source gas is difficult to stabilize, and there is a variation. Easy to occur. This variation is particularly remarkable when the supply amount of the source gas is changed during the process as shown in FIG. This is a factor that causes a variation in the film thickness when, for example, the film is formed by CVD.

[0006]

According to the present invention, there is provided a method of supplying a source gas generated by bubbling of a liquid source.
Perform the steps. First, in a first step, a set value of the supply amount of the source gas is obtained. Next, in a second step, a liquid source is bubbled by supplying an inert gas to generate a source gas. In the third step, the supply amount of the generated source gas is measured to obtain a measured value. In the fourth step, it is determined whether or not the measured value is within a predetermined range of the set value. When it is determined that the measured value is not, the process proceeds to the fifth step, and when it is determined that the measured value is present, the process proceeds to the sixth step. In the fifth step, the supply amount of the inert gas is adjusted so that the measured value approaches the set value, and the process returns to the third step. In the sixth step, the supply amount of the inert gas is fixed.

In the above source gas supply method, the supply amount of the source gas is set by repeatedly measuring the supply amount of the source gas generated by the bubbling and adjusting the supply amount of the inert gas for bubbling. Closer to the value. When the measured value falls within a predetermined range with respect to the set value, the supply amount of the inert gas is fixed, and the variation in the generation amount of the source gas is suppressed. As a result, a stable amount of the source gas is supplied within a predetermined range of the set value without previously obtaining the relationship between the supply amount of the inert gas and the supply amount of the source gas.

The source gas supply device of the present invention used in the above method is a bubbler having one end of an inert gas supply pipe and one end of a source gas supply pipe inserted into a liquid source tank. Flow controller provided in the pipe,
A flow measuring device provided in the source gas supply pipe and a control circuit connected to the flow regulator and the flow measuring device are provided. In this control circuit, a set value of the supply amount of the source gas is input in advance. At the same time, the control circuit controls the flow controller so as to bring the measured value close to the set value until the measured value obtained by the flow meter falls within the predetermined range of the set value. The gas supply amount is adjusted, and the flow rate controller is controlled so as to fix the inert gas supply amount when the measured value falls within a predetermined range of the set value.

The above-described source gas supply method is performed by using the source gas supply device having the above configuration.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a source gas supply method and a source gas supply device according to the present invention will be described below with reference to the drawings. FIG. 1 is a flowchart illustrating a source gas supply method, and FIG. 2 is a configuration diagram of the source gas supply device. First, the configuration of the source gas supply device used in the source gas supply method will be described with reference to FIG.

As shown in FIG. 2, a source gas supply device 1
Are provided in a sealed liquid source tank 11, a heater 12 provided on the lower surface of the liquid source tank 11, an inert gas supply pipe 13 having one end inserted into the liquid source tank 11, and an inert gas supply pipe 13. A flow controller (so-called mass flow controller) 14, a source gas supply pipe 15 having one end inserted into the liquid source tank 11, a flow meter (so-called mass flow meter) 16 provided in the source gas supply pipe 15, And a control circuit 17 connected to the flow controller 14 and the flow measuring device 16.

The liquid source tank 11 is connected to a supply tank 21 for the liquid source L by a liquid source supply pipe 22, and is supplied by an inert gas pressure supplied from the supply pipe 23 into the supply tank 21. The liquid source L is supplied from 21.

The heater 12 comprises a liquid source tank 11
This is for heating the liquid source L inside. Also,
The inert gas supply pipe 13 is for supplying an inert gas for bubbling the liquid source L in the liquid source tank 11, and one end thereof is inserted into the liquid source L in the liquid source tank 11. It is provided to be. The flow controller 14 controls the flow rate of the inert gas supplied from the inert gas supply pipe 13 into the liquid source tank 11.

Further, the source gas supply pipe 15 is for supplying a source gas generated by bubbling of the liquid source L into the reaction chamber 31. One end inserted into the liquid source tank 11 has: It is arranged on the liquid source L in the liquid source tank 11. The flow rate measuring device 16 is connected to the reaction chamber 3 from the source gas supply pipe 15.
This is for measuring the flow rate of the source gas supplied into the apparatus.

Further, the control circuit 17 receives the set value of the supply amount of the source gas to the reaction chamber 31 and, based on the measured value obtained by the flow rate measuring device 16 and the inputted set value. Gas supply pipe 1 by flow controller 14
3 is to control the supply amount of the inert gas. The control of the supply amount of the inert gas by the control circuit 17 is performed as follows. That is, the supply amount of the inert gas is adjusted so that the measured value approaches the set value until the measured value falls within the predetermined range of the set value. On the other hand, when the measured value falls within the predetermined range of the set value, the supply amount of the inert gas is fixed.

Next, a source gas supply method using the source gas supply device having the above configuration will be described with reference to the flowcharts of FIGS. Here, the control circuit 1
7 will be described in detail.

First, in the first step S1, the reaction chamber 31
The set value is obtained by setting the supply amount of the source gas to. Here, the supply amount of the source gas required in the processing step in the reaction chamber 31 is set as the set value, and the set value is input to the control circuit 17.

Next, in a second step S2, an inert gas is supplied into the liquid source L in the liquid source tank 11 to bubble the liquid source. As a result, a source gas in which the liquid source L is vaporized is generated in the liquid source tank 11. At this time, as the initial value of the supply amount of the inert gas, for example, a value derived from past experience is applied.

Thereafter, in a third step S3, the flow rate of the source gas generated in the liquid source tank 11 and flowing through the source gas supply pipe 15 is measured by the flow rate measuring device 16.

Next, in a fourth step S4, the measured value measured in the third step S3 is compared with the first step S3.
Within a predetermined range of the set value set in 1, for example, ± 5 of the set value
The control circuit 17 determines whether or not the value is within%. The above range is set to any value that does not affect the processing steps in the reaction chamber 31. If the measured value is not within the range, the process proceeds to a fifth step S5. If the measured value is within the range, the process proceeds to a sixth step S6.

When the process proceeds to the fifth step S5, the control circuit 17 controls the flow controller 14 to adjust the supply amount of the inert gas so that the measured value approaches the set value. . For example, when the measured value is a value exceeding the set value range, the flow controller 14 is controlled so as to reduce the supply amount of the inert gas, and when the measured value is a value below the set value range, Controls the flow controller 14 to increase the supply amount of the inert gas. Thereafter, the process returns to the third step S3, and the third step S3 and the fourth step S4 are repeatedly performed.

On the other hand, when the process proceeds to the sixth step S6, the supply amount of the inert gas is fixed by controlling the flow controller 14 by the control circuit 17. After fixing the supply amount of the inert gas as described above, the process in the reaction chamber 31 is started. Thereafter, the reaction chamber 31
Until the processing step in the inside is completed, the supply of the source gas is continued by bubbling the liquid source L while the supply amount of the inert gas is fixed.

In the above-described source gas supply method and the apparatus used in this method, the measurement of the supply amount of the inert gas and the adjustment of the supply amount of the inert gas are repeatedly performed, so that the source gas from the source gas supply pipe 15 is To the set value. Therefore, the supply amount of the source gas can be made close to the set value without taking the trouble of previously obtaining the relationship between the supply amount of the inert gas and the supply amount of the source gas. At the same time, when the measured value falls within the predetermined range of the set value, the supply amount of the inert gas is fixed. Then, after the supply amount of the inert gas is fixed, the variation in the generation amount of the source gas is suppressed. FIG. 3 is a graph showing a change over time in the supply amount of the source gas according to the above procedure. As shown in this graph, after the supply amount of the inert gas is fixed, the supply amount of the source gas into the reaction chamber 31 is stabilized within a predetermined range of the set value. Therefore, in the reaction chamber 31, the processing can be performed in a stable supply amount of the source gas atmosphere. For example, in the case where the film formation process is performed in the reaction chamber 31, the supply amount of the film formation gas (source gas) is stabilized, so that the controllability of the film thickness can be improved.

When the process is performed by continuously changing the supply amount of the source gas, two-stage set values are input to the control circuit 17, and after the first-stage process is completed, the second-stage set value is inputted. The control circuit 17 controls the flow controller 1 so that the measured value of the supply amount of the source gas falls within a predetermined range with respect to the set value.
4 is controlled. Then, after the measured value falls within the range of the second-stage set value and the supply amount of the inert gas is fixed again, the second-stage processing step is started in the reaction chamber 31.

[0025]

As described above, according to the source gas supply method and the source gas supply apparatus of the present invention, when the source gas generated by the bubbling of the liquid source by the supply of the inert gas is supplied, the inert gas is supplied in advance. The source gas supply amount can approach the set value without taking the trouble of obtaining the relationship between the gas supply amount and the source gas supply amount, and the source having a stable supply amount near the set value can be obtained. It becomes possible to supply gas. Therefore, it is possible to simplify and stabilize the process using the source gas.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an embodiment of a source gas supply method according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a source gas supply device of the present invention.

FIG. 3 is a graph showing a change over time in a supply amount of a source gas according to the present invention.

FIG. 4 is a graph showing a change over time of a supply amount of a source gas by an open loop method.

FIG. 5 is a graph showing a change over time of a source gas supply amount by a closed loop method.

[Explanation of symbols]

10 Bubbler, 11 Liquid source tank, 13 Inert gas supply pipe, 14 Flow regulator, 15 Source gas supply pipe, 16 Flow meter, 17 Control circuit

Claims (2)

[Claims] 1. A method for supplying a source gas generated by bubbling a liquid source, comprising: a first step of obtaining a set value of a supply amount of the source gas; and bubbling the liquid source by supplying an inert gas. A second step of generating the source gas, a third step of measuring a supply amount of the generated source gas to obtain a measured value, and determining whether the measured value is within a predetermined range of the set value. If the judgment is negative, the process proceeds to a fifth step. If the judgment is negative, the process proceeds to a sixth step. The supply of the inert gas so that the measured value approaches the set value. A source gas supply method, comprising: performing a fifth step of adjusting the amount and returning to the third step; and a sixth step of fixing the supply amount of the inert gas. 2. An apparatus for supplying a source gas generated by bubbling a liquid source, comprising: a bubbler having one end of an inert gas supply pipe and one end of a source gas supply pipe inserted into a liquid source tank. A flow controller provided in the inert gas supply pipe; a flow meter provided in the source gas supply pipe; a flow controller connected to the flow controller and the flow meter, and supplying the source gas in advance. When the set value of the quantity is input,
Until the measured value obtained by the flow rate measuring device falls within a predetermined range of the set value, the flow rate controller is controlled to adjust the supply amount of the inert gas so that the measured value approaches the set value. A control circuit for controlling the flow regulator so that the supply amount of the inert gas is fixed when the measured value falls within a predetermined range of the set value. Feeding device.