Method and apparatus for pulse gas delivery with concentration measurement
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.
1. 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; and
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.
2. The system of claim 1 , wherein 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.
3. The system of claim 1 , wherein the gas concentration measurement system comprises an optical gas sensor, a surface acoustic wave device, an ultrasound sensor, a mass spectrometer or a thermal conductive detector.
4. The system of claim 1 , wherein the gas concentration measurement system is arranged in series between a source of the gas mixture and the pulse gas delivery system, to receive the gas mixture from a source and to provide the gas mixture to the pulse gas delivery system.
5. The system of claim 1 , wherein the gas concentration measurement system is arranged to receive a sample of the gas mixture from a sample line that samples a gas flow of the gas mixture from a source to the pulse gas delivery system.
6. The system of claim 1 , wherein the process chamber to which the pulse gas delivery system is configured to deliver the process gas is one of: an Atomic Layer Deposition (ALD) process, an Atomic Layer Etch (ALE) process, a Through Silicon Via (TSV) process, a pulsed deep reactive ion etch (DRIE) process, a plasma enhanced chemical vapor deposition (CVD) process and a plasma enhanced etching process.
7. 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;
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; and
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.
8. The method of claim 7 , comprising setting an initial target flow setpoint of the gas mixture in inverse proportion to the received concentration of the process gas.
9. The method of claim 7 , comprising measuring the concentration of the process gas in the gas mixture using an optical gas sensor, a surface acoustic wave device, an ultrasound sensor, a mass spectrometer or a thermal conductive detector.
10. The method of claim 7 , comprising using the pulse gas delivery system to deliver the process gas to one of: an Atomic Layer Deposition (ALD) process, an Atomic Layer Etch (ALE) process, a Through Silicon Via (TSV) process, a pulsed deep reactive ion etch (DRIE) process, a plasma enhanced chemical vapor deposition (CVD) process and a plasma enhanced etching process.
11. 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; and
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; and
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.
12. 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; and
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; and
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 Q sp (t) is the flow setpoint, k is a mole to flow unit conversion constant, M sp is a process gas mole delivery per pulse setpoint, Q m 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 t 0 is an initial time of the pulse duration period.
13. 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; and
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; and
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.
14. 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; and
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 Q sp (t) is the flow setpoint, k is a mole to flow unit conversion constant, M sp is a process gas mole delivery per pulse setpoint, Q m 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 t 0 is an initial time of the pulse duration period.