JPH04291122A - Instrument for measuring evaporation of liquid raw material - Google Patents

Abstract

PURPOSE:To obtain a device for measuring evaporation of liquid raw materials, which is improved in the evaporation measuring accuracy, by improving the measuring accuracy of weight changes caused by the evaporation of a liquid raw material. CONSTITUTION:The total weight of a raw material tank 3 installed on one side of a balance device 4 from a fulcrum is measured while most of the total weight of the tank 3 is supported by acting the weight moment of a counter balance 6 installed on the other side of the device from the fulcrum to the tank 3 and supporting the remaining weight of the tank with a weighing instrument 5. When the weight supported by the instrument 5 is reduced, the instrument 5 can be reduced in the indication of the minimum weighing weight and the measuring accuracy of the total weight of the tank 3 can be improved. Therefore, the evaporation measuring accuracy of the titanium tetrachloride liquid 2a contained in the tank 3 can be improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for measuring the amount of evaporation of a liquid raw material, which is particularly suitable for measuring the amount of evaporation of a liquid raw material having a high vaporizability.

0002

2. Description of the Related Art A conventional liquid raw material evaporation amount measuring device will be described below.

For example, when producing a TiN film using a CVD apparatus, titanium tetrachloride (TiCl4) is used as a liquid raw material.

[0004] Titanium tetrachloride is evaporated while being stored in a raw material tank. When introducing titanium tetrachloride gas produced by vaporization into the CVD chamber from the raw material tank, the flow rate of titanium tetrachloride gas is adjusted by measuring the amount of evaporation of liquid titanium tetrachloride in the raw material tank and converting it. do.

The amount of evaporation is measured by measuring the change in the weight of liquid titanium tetrachloride in the raw material tank.

Conventionally, liquid titanium tetrachloride in a raw material tank has been weighed using an evaporation amount measuring device consisting of a weighing device and an evaporation amount conversion device that converts the evaporation amount of liquid titanium tetrachloride from the measured value of this weighing device. Let's do it.

[0007] That is, the weight of liquid titanium tetrachloride is calculated from the measured value measured by a weighing device that supports the total weight of the raw material tank. Then, the amount of evaporation of the liquid titanium tetrachloride is calculated by converting the weight change of the liquid titanium tetrachloride from the change in the measured value of the weighing device.

[0008]

[Problems to be Solved by the Invention] However, in the case of the evaporation measuring device configured as described above, it is not possible to support the entire weight of both the raw material tank and the liquid titanium tetrachloride stored in this raw material tank. However, there was a problem in that it was not suitable for measuring the amount of evaporation of liquid titanium tetrachloride.

That is, the amount of evaporation of liquid titanium tetrachloride is
Since the change in the weight of the liquid titanium tetrachloride in the raw material tank due to evaporation is relatively small compared to the total weight supported by the weighing device, the accuracy of the measured value cannot be expected.

[0010] More specifically, when a weighing device has a large maximum weighing capacity, the minimum display of the measured weight generally becomes large and the accuracy decreases, so the accuracy of measuring the amount of evaporation of liquid titanium tetrachloride decreases. .

For example, when the raw material tank weighs 50 kg, it is necessary to use a weighing device whose maximum weighing capacity exceeds at least 50 kg.

However, when adjusting the flow rate of titanium tetrachloride gas by measuring changes in the weight of liquid titanium tetrachloride in the raw material tank in units of one minute, the accuracy of the measured value of the amount of titanium tetrachloride evaporated per minute is , there are cases where less than 1 g is required, so it is minute compared to the total weight of the raw material tank,
The accuracy of measuring changes in the weight of liquid titanium tetrachloride using the weighing device cannot be expected.

At this time, in order to improve the accuracy of measurement, it is necessary to take a longer time to measure the amount of evaporation of liquid titanium tetrachloride in the raw material tank, but in this case, the time required to measure the flow rate of titanium tetrachloride gas is longer. This will take a long time and reduce the accuracy of the adjustment, making it impossible to solve the problem fundamentally.

The present invention has been made in view of the above-mentioned problems, and provides a device for measuring the amount of evaporation of a liquid raw material, which improves the accuracy of measuring the amount of evaporation by increasing the accuracy of measuring the weight change accompanying the evaporation of the liquid raw material. The purpose is to provide

[0015]

[Means for Solving the Problems] The liquid raw material evaporation measuring device of the present invention includes a raw material tank that stores the liquid raw material, a balance device that supports the raw material tank, and a weighing device that measures the weight of the raw material tank together with the balance device. The weighing device is composed of a weighing device and a counterbalance that can be attached to and detached from the balance device, and the weighing device is made up of a support portion and a balance rod whose central portion is rotatably attached using the contact point with the upper part of the support portion as a fulcrum, A feature is that a raw material tank is attached to one side of the balance rod, and a counterbalance of a predetermined weight is attached to the other side.

[0016]

[Operation] According to the liquid raw material evaporation measurement device of the present invention,
By applying a counterbalance weight moment to the raw material tank via a fulcrum, a part of the weight of the raw material tank is supported, and the rest is weighed by a weighing device. Measure while supporting it.

Furthermore, the amount of evaporation of the liquid raw material is measured using a weighing device with a small minimum display of measured weight.

[0018]

Embodiment An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 1 in the figure indicates an apparatus for measuring the amount of evaporation of a liquid raw material (hereinafter simply referred to as an evaporation amount measuring apparatus) of this embodiment.

As shown in FIG. 1, the evaporation amount measuring device 1 of this embodiment is installed in a CVD device S for producing a TiN film.

A raw material tank 3 that stores liquid titanium tetrachloride (liquid raw material) 2a, a balance device 4 that supports this raw material tank 3, a weighing device 5 that measures the weight of the raw material tank 3, and a weighing device 5 that can be attached to and detached from the balance device 4. It is composed of a flexible counterbalance 6.

The raw material tank 3 is shaped like a barrel, and is placed and fixed on one end of the balance device 4. Inside the raw material tank 3, there are a raw material gas pipe 3a for supplying liquid titanium tetrachloride 2a and a raw material gas pipe 3 for guiding the vaporized liquid titanium tetrachloride 2a into the chamber T of the evaporation amount measuring device 1.
b is inserted so as not to contact the raw material tank 3.

A flow rate adjustment device 3c for adjusting the flow rate of liquid titanium tetrachloride 2a is attached to the raw material supply pipe 3a.

The balance device 4 is composed of a support portion 4a and a balance rod 4b rotatably attached to the center portion using the contact point with the upper portion of the support portion 4a as a fulcrum.

A raw material tank 3 is attached to one side of the balance rod 4b, and a counterbalance 6 of a predetermined weight is attached to the other side.
is installed. Further, the upper part of the weighing device 5 is in contact with the lower surface of the balance rod 4b to which the raw material tank 3 is attached.

[0026] The weighing device 5 has a pressure receiving part 5 which is extendable and retractable at the upper part.
a, which supports the weight of the raw material tank 3 with this pressure receiving part 5 biased against the lower surface of the balance device 4, and measures and monitors the loaded weight.

Note that the flow rate adjustment device 3c is configured to operate in conjunction with the measured value of the weighing device 5.

The operation of the evaporation amount measuring device 1 will be explained below.

In the evaporation measuring device 1, first,
The precision of the flow rate adjustment of the titanium tetrachloride gas 2b is set, and the weighing device 5 with the minimum weighing display that can achieve this precision is selected and installed at the position.

Next, the amount of liquid titanium tetrachloride 2a stored in the raw material tank 3 is set, and the total weight of the raw material tank 3, which is the sum of the weights of the raw material tank 3 and the liquid titanium tetrachloride 2a, is the maximum weighing capacity of the weighing device 5. A counterbalance 6 with an appropriate weight is selected so that the weight is less than 1, and is attached to the balance rod 4b at an appropriate distance from the fulcrum of the balance device 4.

When the configuration of the evaporation measuring device 1 is completed, the flow rate adjustment device 3c is operated to start supplying the liquid titanium tetrachloride 2a from the raw material supply pipe 3a to the raw material tank 3.

Most of the total weight of the raw material tank 3 is supported by the moment of the counterbalance 6 acting through the fulcrum.

[0033] Regarding the part of the sum of the total weight of the raw material tank 3 that exceeds the support by the counterbalance 6,
It is supported by a weighing device 5.

In order to measure the amount of evaporation of the liquid titanium tetrachloride 2a in the raw material tank 3 using the evaporation amount measuring device 1, the change in the weight supported by the weighing device 5 is measured per unit time and the value is converted from that value. do.

[0035] Furthermore, by operating the flow rate regulating device 3c in conjunction with the value of the evaporation amount, the supply amount of liquid titanium tetrachloride 2a is adjusted to obtain a predetermined flow rate of titanium tetrachloride gas 2b. .

Evaporation measurement device 1 configured as described above
The total weight of the raw material tank 3 is measured with most of the weight of the raw material tank 3 being supported by applying a moment of weight of a counterbalance 6 via a fulcrum, and the rest being supported by a weighing device 5.

Therefore, the evaporation amount measuring device 1 of this embodiment
According to , since the weight supported by the weighing device 5 can be reduced, it is possible to use a weighing device 5 with a small maximum weighing capacity, and it is also possible to use a weighing device 5 with a small minimum display of measured weight. This makes it possible to increase the accuracy of measuring the total weight of the raw material tank 3, thereby improving the accuracy of measuring the amount of evaporation of the liquid titanium tetrachloride 2a in the raw material tank 3.

Furthermore, as a result of the above, titanium tetrachloride gas 2b
The accuracy of flow rate adjustment is improved.

[0039]

As explained above, according to the liquid raw material evaporation measuring device of the present invention, there is provided a raw material tank for storing the liquid raw material, a balance device that supports the raw material tank, and a balance device that supports the raw material tank together with the balance device. The balance device consists of a weighing device for measuring weight and a counterbalance that can be attached to and detached from the balance device. The feature is that a raw material tank is attached to one side of the balance rod, and a counterbalance of a predetermined weight is attached to the other side, so the sum of the weights of the raw material tank and the total weight of the raw material tank is , most of the weight is supported by applying a counterbalance weight moment to the raw material tank via a fulcrum, and the rest is supported by a weighing device.As a result, it is possible to use a weighing device with a small minimum display of measured weight. By making this possible, the accuracy of measuring the total weight of the raw material tank is increased, and the accuracy of measuring the amount of evaporation of the liquid raw material in the raw material tank is improved.

Furthermore, as a result of the above, the accuracy of adjusting the flow rate of the vaporized liquid raw material is improved.

[Brief explanation of the drawing]

FIG. 1 is an overall view showing an apparatus for measuring the amount of evaporation of a liquid raw material according to the present embodiment.

[Explanation of symbols]

1 Evaporation measurement device for liquid raw materials 2a Liquid titanium tetrachloride 3 Raw material tank 4. Balance device 4a Support part 4b Balance rod 5 Weighing device 6 Counterbalance

Claims (1)

[Claims] Claim 1: Consists of a raw material tank that stores liquid raw materials, a balance device that supports this raw material tank, a weighing device that measures the weight of the raw material tank together with the balance device, and a counterbalance that can be attached to and detached from the balance device. , the balance device is
It consists of a support part and a balance rod that is rotatably attached to the center using the contact point with the upper part of the support part as a fulcrum.A raw material tank is attached to one side of the balance rod, and a container with a predetermined weight is attached to the other side. A liquid raw material evaporation measurement device characterized by being equipped with a counterbalance.