Flow rate measurement apparatus and method for more accurately measuring gas flow to a substrate processing system

Patent metadata

Field	Value
Publication number	US-11326914-B2
Application number	US-201916645898-A
Country	US
Kind code	B2
Filing date	May 27, 2019
Priority date	Jun 8, 2018
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

The flow rate measurement method includes: measuring a first pressure of a gas filled in a first flow path connected to a flow rate controller and a second flow path connected to the first flow path; supplying a gas to the first and second flow paths via the flow rate controller and measuring a second pressure and a temperature of the gas filled in the first and second flow paths; after the gas is exhausted from the second flow path, measuring a third pressure of the gas filled in the second flow path; measuring a fourth pressure of the gas filled in the first and second flow paths; and calculating an amount of the gas supplied to the first and second flow paths via the flow rate controller, based on the first, second, third, and fourth pressures and the temperature.

First claim

What is claimed is:

1. A method of measuring a flow rate, comprising:
providing a connection, at a processing space where a substrate is processed, to a first flow path which is connected to a flow rate controller at a first end of the first flow path, and a second flow path which is connected to the first flow path at a second end of the first flow path;
measuring a first pressure of a remaining gas filled in the first and second flow paths;
after the first pressure is measured, supplying a processing gas to the first and second flow paths via the flow rate controller, and measuring a second pressure and a temperature of the processing gas filled in the first and second flow paths;
after the second pressure is measured, disconnecting the second flow path from the first flow path, and exhausting the processing gas from the second flow path by a pump in communication with the second flow path;
after the processing gas is exhausted from the second flow path, measuring a third pressure in the second flow path;
after the third pressure is measured, connecting the first and second flow paths and measuring a fourth pressure of the processing gas filled in the first and second flow paths; and
determining a flow rate measurement of the processing gas supplied to the first and second flow paths via the flow rate controller, based on the first, second, third, and fourth pressures and the temperature,
wherein the processing gas is supplied by generating a plurality of gas pulses.

2. The method according to claim 1 , wherein the processing gas is supplied to the first and second flow paths in a manner that a process is repeated a plurality of times, the process including:
supplying the processing gas to the first flow path via the flow rate controller; and
stopping the supply of the processing gas to the first flow path via the flow rate controller, after a predetermined time elapses from a timing when the processing gas starts to be supplied to the first flow path via the flow rate controller.

3. The method according to claim 2 , further comprising:
before the first pressure is measured, evacuating the first and second flow paths through the processing space in a manner that the remaining gas in the first and second flow paths is exhausted from the processing space; and
after the first and second flow paths are evacuated, disconnecting the processing space from the first flow path to measure the first pressure,
wherein the first, second, third, and fourth pressures are measured when the processing space is not connected to the first flow path.

4. The apparatus according to claim 3 , wherein in evacuating of the first and second flow paths:
a substitution gas is supplied to the first flow path, and
after the substitution gas is supplied to the first flow path, the first and second flow paths are evacuated in a manner that the substitution gas and the remaining gas are exhausted from the processing space.

5. The method according to claim 1 , further comprising:
before the first pressure is measured, evacuating the first and second flow paths through the processing space in a manner that the remaining gas in the first and second flow paths is exhausted from the processing space; and
after the first and second flow paths are evacuated, disconnecting the processing space from the first flow path to measure the first pressure,
wherein the first, second, third, and fourth pressures are measured when the processing space is not connected to the first flow path.

6. The method according to claim 5 , wherein in evacuating of the first and second flow paths:
a substitution gas is supplied to the first flow path, and
after the substitution gas is supplied to the first flow path, the first and second flow paths are evacuated in a manner that the substitution gas and the remaining gas are exhausted from the processing space.

7. The method according to claim 1 , wherein the determining the flow rate measurement of the processing gas supplied to the first and second flow paths via the flow rate controller includes determining the flow rate by Equation (1) below:
Q=dP/dt× 1/ R ×( V stray/ T stray+ V ext/ T ext+ Vfv/Tfv )  (1),

wherein Q represents the flow rate of the processing gas, dP represents a value obtained by subtracting the first pressure from the second pressure, dt represents a time during which the processing gas is supplied, Vstray represents a volume of the first flow path between the flow rate controller and a valve between the flow rate controller and the processing space, Tstray represents a temperature of the residual gas, Vext represents a volume of the first flow path, Text represents a temperature of the processing gas filled in the first flow path when the second pressure is measured, Vfv represents a volume of the second flow path, and Tfv represents the temperature of the processing gas filled in the first and second flow paths when the second pressure is measured.

8. The method according to claim 1 , further including:
gradually increasing a flow rate of the processing gas supplied to the first and second flow paths via the flow rate controller at a first timing after the supply of the processing gas is started,
after a second timing when the flow rate reaches a predetermined set flow rate after the first timing, the flow rate is fixed in a substantially equal state to the predetermined set flow rate,
at a third timing a first predetermined time after the first timing, the supply of the processing gas is stopped and the flow rate decreases gradually after the third timing, and
at a fourth timing succeeding the third timing, the flow rate is substantially equal to 0.

9. The method according to claim 8 , further including controlling a period between the first and second timings and a period between the third and fourth timings to be shorter than a second predetermined time.

10. The method according to claim 1 , wherein an amount of the processing gas supplied to the first and second flow paths via the flow rate controller is adjusted by adjusting a number of the plurality of gas pulses.

11. The method according to claim 1 , wherein the second pressure is obtained by calculating an average of a plurality of pressures measured at different positions in the second flow path.

12. An apparatus of measuring a flow rate, comprising:
a connection, at a processing space where a substrate is processed, to a first flow path which is connected to a flow rate controller at a first end of the first flow path, and a second flow path which is connected to the first flow path at a second end of the first flow path;
a first valve provided between the processing space and the first flow path;
a second valve provided between the first and second flow paths;
a pressure sensor configured to measure a pressure of a gas filled in the second flow path;
a temperature sensor configured to measure a temperature of the gas filled in the second flow path; and
a controller configured to:
control the pressure sensor to measure a first pressure of a remaining gas filled in the first and second flow paths,
after the first pressure is measured, control the flow rate controller to supply a processing gas to the first and second flow paths via the flow rate controller,
after the processing gas is supplied to the first and second flow paths, control the pressure sensor to measure a second pressure and a temperature of the processing gas filled in the first and second flow paths,
after the second pressure is measured, control the second valve to disconnect the first and second flow paths from each other, and exhaust the processing gas from the second flow path by a pum

Assignees

• Tokyo Electron Ltd

Inventors

• Amikura Norihiko
• Matsuda risako
• Miura Kazuyuki

Classifications

• G01F25/10

  of flowmeters · CPC title

• G01F1/50 Primary

  Correcting or compensating means · CPC title

• G01F15/005

  Valves (valves in general F16K) · CPC title

• G01F1/363 Primary

  with electrical or electro-mechanical indication (G01F1/37 and G01F1/38 take precedence) · CPC title