Method and apparatus for pulse gas delivery with concentration measurement
AssigneeMKS Instruments, Inc.
InventorsHongke Ye, Vidi Saptari, Junhua Ding
Life of this patent
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Abstract
A system and method provides a more precise mole delivery amount of a process gas, for each pulse of a pulse gas delivery, by measuring a concentration of the process gas and controlling the amount of gas mixture delivered in a pulse of gas flow based on the received concentration of the process gas. The control of mole delivery amount for each pulse can be achieved by adjusting flow setpoint, pulse duration, or both.
Claims30
A pulse gas control system, the system comprising:
- a gas concentration measurement system configured to measure a concentration of a process gas in a gas mixture;
- a pulse gas delivery system including a sensor to sense flow of the gas mixture and a control valve to regulate flow of the gas mixture to a flow setpoint during a pulse duration period, the pulse gas delivery system receiving the measured concentration of the process gas in the gas mixture, measured by the gas concentration measurement system, and adjusting the flow setpoint, during the pulse duration period, based on a changed measured concentration during the pulse duration period to control an amount of gas mixture delivered in a pulse of gas flow, based on the measured concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber during the pulse duration period;
- the pulse gas delivery system maintaining a constant pulse duration while adjusting the flow setpoint over time during the pulse duration period until the pulse duration period is complete and a total process gas mole delivery per pulse setpoint is reached, the adjusting comprising adjusting the flow setpoint over time during the pulse duration period based on the remaining time within the pulse and the remaining mole amount of process gas to be delivered within the pulse out of the total process gas mole delivery per pulse setpoint;
- and
- a heater configured to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
A method of controlling a pulse gas delivery system, the method comprising:
- measuring a concentration of a process gas in a gas mixture using a gas concentration measurement system;
- with the pulse gas delivery system, receiving the measured concentration of the process gas in the gas mixture, the pulse gas delivery system including a sensor to sense flow of the gas mixture and a control valve to regulate flow of the gas mixture to a flow setpoint during a pulse duration period;
- and
- adjusting the flow setpoint, during the pulse duration period, based on a changed measured concentration during the pulse duration period to control an amount of gas mixture delivered in a pulse of gas flow by the pulse gas delivery system, based on the measured concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber during the pulse duration period;
- maintaining a constant pulse duration while adjusting the flow setpoint over time during the pulse duration period until the pulse duration period is complete and a total process gas mole delivery per pulse setpoint is reached, the adjusting comprising adjusting the flow setpoint over time during the pulse duration period based on the remaining time within the pulse and the remaining mole amount of process gas to be delivered within the pulse out of the total process gas mole delivery per pulse setpoint;
- and
- using a heater to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
A pulse gas control system, the system comprising:
- a gas concentration measurement system configured to measure a concentration of a process gas in a gas mixture;
- a pulse gas delivery system configured to sense flow of the gas mixture and control flow of the gas mixture and to receive the concentration of the process gas in the gas mixture, measured by the gas concentration measurement system, and to control an amount of gas mixture delivered in a pulse of gas flow, based on the received concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber in the pulse;
- wherein the pulse gas delivery system is configured to adjust a flow setpoint of the gas mixture during the pulse based on the received concentration of the process gas, and the pulse gas delivery system sets an initial target flow setpoint of the gas mixture in inverse proportion to the received concentration of the process gas;
- wherein the pulse gas delivery system sets the initial target flow setpoint in proportion to a process gas mole delivery per pulse setpoint divided by a product of a pulse duration period multiplied by the received concentration of the process gas;
- and
- a heater configured to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
A pulse gas control system, the system comprising:
- a gas concentration measurement system configured to measure a concentration of a process gas in a gas mixture;
- a pulse gas delivery system configured to sense flow of the gas mixture and control flow of the gas mixture and to receive the concentration of the process gas in the gas mixture, measured by the gas concentration measurement system, and to control an amount of gas mixture delivered in a pulse of gas flow, based on the received concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber in the pulse;
- wherein the pulse gas delivery system is configured to adjust a flow setpoint of the gas mixture during the pulse;
- wherein the pulse gas delivery system adjusts the flow setpoint, during a pulse duration period, based on a changed measurement of the process gas concentration during the pulse duration period, based on a relationship:
- Q
- sp
- (
- t
- )
- =
- k
- ·
- M
- sp
- -
- ∫
- t
- 0
- t
- Q
- m
- (
- t
- )
-
- C
-
- (
- t
- )
-
- dt
- (
- Δ
-
- t
- -
- (
- t
- -
- t
- 0
- )
- )
- ·
- C
-
- (
- t
- )
- where Qsp(t) is the flow setpoint, k is a mole to flow unit conversion constant, Msp is a process gas mole delivery per pulse setpoint, Qm(t) is a measured flow rate of the pulse gas delivery system, C(t) is the received process gas concentration, Δt is the pulse duration period, t is a current time, and t0 is an initial time of the pulse duration period;
- and
- a heater configured to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
A method of controlling a pulse gas delivery system, the method comprising:
- measuring a concentration of a process gas in a gas mixture;
- with the pulse gas delivery system, receiving the concentration of the process gas in the gas mixture;
- controlling an amount of gas mixture delivered in a pulse of gas flow by the pulse gas delivery system, based on the received concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber in the pulse;
- the controlling comprising adjusting a flow setpoint of the gas mixture during the pulse based on the received concentration of the process gas, and setting an initial target flow setpoint of the gas mixture in inverse proportion to the received concentration of the process gas;
- the setting of the initial target flow setpoint being in proportion to a process gas mole delivery per pulse setpoint divided by a product of a pulse duration period multiplied by the received concentration of the process gas;
- and
- using a heater to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
A method of controlling a pulse gas delivery system, the method comprising:
- measuring a concentration of a process gas in a gas mixture;
- with the pulse gas delivery system, receiving the concentration of the process gas in the gas mixture;
- controlling an amount of gas mixture delivered in a pulse of gas flow by the pulse gas delivery system, based on the received concentration of the process gas, to control a mole amount of the process gas delivered to a process chamber in the pulse, the controlling comprising adjusting a flow setpoint of the gas mixture during the pulse;
- the adjusting the flow setpoint comprising adjusting the flow setpoint, during a pulse duration period, based on a changed measurement of the process gas concentration during the pulse duration period based on a relationship:
- Q
- sp
- (
- t
- )
- =
- k
- ·
- M
- sp
- -
- ∫
- t
- 0
- t
- Q
- m
- (
- t
- )
-
- C
-
- (
- t
- )
-
- dt
- (
- Δ
-
- t
- -
- (
- t
- -
- t
- 0
- )
- )
- ·
- C
-
- (
- t
- )
- where Qsp(t) is the flow setpoint, k is a mole to flow unit conversion constant, Msp is a process gas mole delivery per pulse setpoint, Qm(t) is a measured flow rate of the pulse gas delivery system, C(t) is the received process gas concentration, Δt is the pulse duration period, t is a current time, and t0 is an initial time of the pulse duration period;
- and
- using a heater to maintain at least part of the flow of the gas mixture comprising the process gas at an elevated temperature.
Dependencies are inferred from the claim text.