JPH04161241A - Gas supply device - Google Patents

Abstract

PURPOSE:To ensure that a specified gas flow volume is stably supplied by providing a mass flow meter which monitors each gas flow volume to be supplied to a chamber and a bypass valve which allows gas supply to bypass the mass flow meter based on gas flow variations. CONSTITUTION:The flow volumes of various gases to be supplied to a chamber 4 which stores a semi-conductor substrate are detected by a mass flow meter 3. In addition, a gas volume designation controller 10 compares the actual gas flow volume with reference setting values of various gases of the meter 3, then calculates either a gas excess or a gas shortage and converts this calculated value to a time-related signal. In addition, a bypass valve 8 bypasses the supply of various gases directly from a gas supply source, instead of passing through each mass flow controller 1 and a valve 2. Then the controller 10 opens the valve 8 for a time corresponding to the time-related signal using the signal and supplies the gas to the chamber 4. Subsequently, the set amount of gas can stably be supplied, if the mass flow controller operates erroneously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a gas supply device that supplies a processing gas to a processing device that diffuses impurities and forms a thin film on a semiconductor substrate.

[Conventional technology]

Conventionally, this type of gas supply device is a device that forms an impurity layer or a thin film on the surface of a semiconductor substrate, for example,
They are attached to thermal diffusion furnaces, CVD equipment, etc., and precise control of the amount of gas to be supplied has been required.

FIG. 2 is a block diagram showing an example of a conventional gas supply device. Normally, this gas supply device, as shown in the same figure,
Piping connected to a chamber 4 evacuated to a predetermined high vacuum by a turbo pump 5 and a rotary pump 6, a plurality of valves 2 for various gases, a mass flow controller 1 connected to each of these valves 2, It has a controller 7 and a control device 9 that command and control the flow rates of various gases supplied from the mass flow controller 1.

Such a gas supply device is connected to the chamber 4 that houses the semiconductor substrate, and the flow rate of various gases is controlled by the mass flow controller 1 depending on the work content to perform processing.

[Problem to be solved by the invention]

However, in the conventional gas supply device described above, the gas flow rate is controlled only by the mass flow controller, so if the mass flow controller malfunctions, the supplied gas flow rate changes and the characteristics of the film of the fabricated semiconductor substrate are affected. It has the disadvantage of causing abnormalities.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gas supply device that stably supplies a set gas flow rate even if a mass flow controller malfunctions, in order to eliminate such drawbacks.

[Means to solve the problem]

The gas supply device of the present invention is a gas supply device that supplies a plurality of types of gases to a chamber accommodating a semiconductor substrate through a plurality of gas flow controllers while keeping a constant flow rate ratio. The mass flow meter that detects the gas is compared with the standard quantitative value of each of the gases of this gas flow meter 3, and either the shortage or excess of the gas is calculated and this calculated value is converted into a signal related to time. Equipped with a gas amount designation controller and a bypass valve that bypasses each mass flow controller 1 and valve 2 and supplies various gases from a gas source,
The bypass valve is opened for a time corresponding to the signal in response to the time-related signal, and the gas is supplied to the chamber.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a waste feeding device according to the present invention. As shown in the figure, this gas supply device includes a mass flow meter 3 that detects the flow rate of various gases in the chamber 4, and a mass flow meter 3 that detects the flow rate of various gases in the chamber 4. A gas amount specifying controller 10 that calculates the amount of gas and converts this shortage or excess into a time signal, and a bypass valve that bypasses each mass flow controller 1 and valve 2 and supplies various gases from the gas source are provided. .

The gas amount specification controller 10 includes a comparator that compares the current value from the mass flow meter 3 with a reference value, a calculator that calculates the difference from the reference value, and converts the amount calculated by this calculator into a unit of time. It has a converter for Furthermore, the bypass valve 8 operates independently of the mass flow controller 1 and is directly connected to a gas supply pipe that supplies gas and a pipe adjacent to the chamber 4 .

Further, when there is an excess or deficiency in the amount of gas in the chamber 4 due to malfunction of the mass flow controller 1, the gas is replenished through the bypass valve 8.

Next, the operation of this gas supply device will be explained. First, for example, when one of the mass flow controllers 1 malfunctions and the amount of a specific gas is insufficient, the gas amount designation controller 10 selects a current value indicating the amount of the gas from the mass flow meter 3 and a predetermined standard. Compare the value and calculate the shortfall. At the same time, the valve 2 that controls the flow rate of the specific gas is closed via the controller 7a. Next, the calculated shortfall is converted into a time-related signal.

The converted signal is sent to the control 7a, which opens the bypass valve 8 for the converted time and supplies the specified gas to the chamber. Next, the amount of gas supplied is measured by the gas flow meter 3.

Next, if it is insufficient, repeat the above operation.

Also, if a specific gas is in excess, close the gas flow controller valve 2 for that specific gas and operate only the other gas flow controllers until the ratio of the other gas and the specific gas becomes constant. Hold. Of course, the gas flow meter 3 always continues to detect the gas flow rate.

〔Effect of the invention〕

As explained above, by providing a gas flow meter that monitors the flow rate of each gas supplied to the chamber, and a bypass valve that bypasses the gas flow controller and supplies gas based on changes in the flow rate, the gas flow controller can be controlled. This has the effect of providing a gas supply device that can always supply each gas at a constant flow rate ratio even if a malfunction occurs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a gas supply device according to the present invention, and FIG. 2 is a block diagram showing an example of a conventional gas supply device. 1... Gas flow controller, 2... Valve, 3
...Gas flow meter, 4...Chamber, 5...
Tarho bomb, 6...rotary pump, 7,7a...
- Controller, 8... Bypass valve, 9... Control device, 10... Gas amount specification controller.

Claims (1)

[Claims] A gas supply device that supplies a plurality of types of gases at a constant flow rate ratio through a plurality of gas flow controllers to a chamber accommodating a semiconductor substrate includes a mass flow meter that detects the flow rate of the various gases in the chamber 4; A gas amount designation controller that compares the gas flow meter 3 with a standard quantitative value of each of the gases, calculates either a shortage or an excess of the gas, and converts this calculated value into a signal related to time, and each mass flow controller. 1 and a bypass valve for supplying various gases from a gas source by bypassing valves 1 and 2, and in response to the time-related signal, the bypass valve is opened for a time corresponding to the signal, and the gas is supplied to the chamber. Characteristic gas supply equipment.