Duty cycle control to achieve uniformity
A method for achieving a first uniformity level in a processing rate across a surface of a substrate is described. The method includes receiving the first uniformity level to be achieved across the surface of the substrate and identifying a first plurality of duty cycles associated with a first plurality of states based on the first uniformity level. The first plurality of states are of a variable of a first radio frequency (RF) signal. The method further includes controlling an RF generator to generate the first RF signal having the first plurality of duty cycles.
1 . A method for achieving a uniformity level in a processing rate across a surface of a substrate, comprising:
receiving a first uniformity level to be achieved across the surface of the substrate;
identifying a first plurality of duty cycles associated with a first plurality of states based on the first uniformity level, wherein the first plurality of states are of a variable of a first radio frequency (RF) signal;
receiving a second uniformity level to be achieved across the surface of the substrate;
identifying a second plurality of duty cycles associated with a second plurality of states based on the second uniformity level, wherein the second plurality of states are of a variable of a second RF signal; and
controlling an RF generator to generate the second RF signal having the second plurality of duty cycles to achieve the second uniformity level, wherein the second RF signal having the second plurality of duty cycles is generated by the RF generator that is coupled to a substrate support of a plasma chamber.
2 . The method of claim 1 , further comprising:
accessing, from a memory device, a listing having a one-to-one correspondence between the second uniformity level and the second plurality of duty cycles,
wherein said identifying the second plurality of duty cycles includes determining that the second plurality of duty cycles correspond to the second uniformity level in the listing, and
wherein said controlling the RF generator includes sending a recipe signal having the second plurality of duty cycles to the RF generator.
3 . The method of claim 2 , wherein said controlling the RF generator includes sending a trigger signal to the RF generator after said sending the recipe signal.
4 . The method of claim 1 , wherein a number of the second plurality of states is unequal to a number of the first plurality of states.
5 . The method of claim 1 , wherein the first plurality of duty cycles and the second plurality of duty cycles repeat with each clock cycle.
6 . The method of claim 1 , wherein the variable of the first RF signal is power or frequency and the variable of the second RF signal is power or frequency.
7 . The method of claim 1 , wherein each of the first plurality of duty cycles is a time period that occurs during a clock cycle, wherein each of the first plurality of states represents a peak-to-peak amplitude of the first RF signal, wherein each of the second plurality of duty cycles is a time period that occurs during the clock cycle, wherein each of the second plurality of states represents a peak-to-peak amplitude of the second RF signal.
8 . The method of claim 1 , wherein the first plurality of states include a first plurality of variable levels of the variable of the first RF signal, wherein each of the first plurality of variable levels is a peak-to-peak envelope of the variable of the first RF signal, wherein the second plurality of states include a second plurality of variable levels of the variable of the second RF signal, wherein each of the second plurality of variable levels is a peak-to-peak envelope of the variable of the second RF signal.
9 . A method for achieving a uniformity level in a processing rate across a surface of a substrate, comprising:
receiving a first uniformity level to be achieved across the surface of the substrate;
identifying a first plurality of duty cycles associated with a first plurality of states of a variable based on the first uniformity level, wherein the first plurality of states are of a first plurality of radio frequency (RF) signals;
receiving a second uniformity level to be achieved across the surface of the substrate;
identifying a second plurality of duty cycles associated with a second plurality of states based on the second uniformity level, wherein the second plurality of states are of a second plurality of RF signals; and
controlling a plurality of RF generators to generate the second plurality of RF signals having the second plurality of duty cycles to achieve the second uniformity level, wherein the second plurality of RF signals having the second plurality of duty cycles are generated by the RF generator that is coupled to a substrate support of a plasma chamber.
10 . The method of claim 9 , wherein the second plurality of duty cycles include a first set of duty cycles, a second set of duty cycles, and a third set of duty cycles, wherein the second plurality of states include a first set of states, a second set of states, and a third set of states, wherein the second plurality of RF signals include a first RF signal, a second RF signal, and a third RF signal, wherein said identifying the second plurality of duty cycles includes:
identifying the first set of duty cycles associated with the first set of states based on the second uniformity level, wherein the first set of states are of the variable of the first RF signal;
identifying the second set of duty cycles associated with the second set of states based on the second uniformity level, wherein the second set of states are of the variable of the second RF signal; and
identifying the third set of duty cycles associated with the third set of states based on the second uniformity level, wherein the third set of states are of the variable of the third RF signal.
11 . The method of claim 10 , wherein the plurality of RF generators includes a first RF generator, a second RF generator, and a third RF generator, wherein said controlling the plurality of RF generators includes:
controlling the first RF generator to generate the first RF signal;
controlling the second RF generator to generate the second RF signal;
controlling the third RF generator to generate the third RF signal.
12 . The method of claim 9 , wherein the second plurality of duty cycles includes a first set of duty cycles, a second set of duty cycles, and a third set of duty cycles, wherein the plurality of RF generators include a first RF generator, a second RF generator, and a third RF generator, the method further comprising:
accessing, from a memory device, a listing having a one-to-one correspondence between the second uniformity level and the second plurality of duty cycles,
wherein said identifying the second plurality of duty cycles includes determining that the second plurality of duty cycles correspond to the second uniformity level in the listing, and
wherein said controlling the plurality of RF generators includes:
sending a first recipe signal having the first set of duty cycles to the first RF generator;
sending a second recipe signal having the second set of duty cycles to the second RF generator; and
sending a third recipe signal having the third set of duty cycles to the third RF generator.
13 . The method of claim 12 , wherein said controlling the plurality of RF generators includes sending a trigger signal to the plurality of RF generators after said sending the first, second, and third recipe signals.
14 . The method of claim 9 , wherein the second plurality of RF signals include a first RF signal, a second RF signal, and a third RF signal, wherein the plurality of RF generators include a first RF generator, a second RF generator, and a third RF generator, wherein the second plurality of states include a first set of states of the variable of the first RF signal, a second set of states of the variable of the second RF signal, and a third set of states of the variable of the third RF signal.
15 . A controller for achieving a uniformity level in a processing rate across a surface of a substrate, comprising:
a processor configured to:
receive a first uniformity level to be achieved across the surface of the substrate;
identify a first plurality of duty cycles associated with a first plurality of states based on the first uniformity level, wherein the first plurality of states are of a variable of a first radio frequency (RF) signal;
receive a second uniformity level to be achieved across the surface of the substrate;
identify a second plurality of duty cycles associated with a second plurality of states based on the second uniformity level, wherein the second plurality of states are of a variable of a second RF signal; and
control an RF generator to generate the second RF signal having the second plurality of duty cycles to achieve the second uniformity level, wherein the second RF signal having the second plurality of duty cycles is generated by the RF generator that is coupled to a substrate support of a plasma chamber; and
a memory device coupled to the processor, wherein the memory device is configured to store the first and second uniformity levels.
16 . The controller of claim 15 , wherein the processor is configured to:
access, from the memory device, a listing having a one-to-one correspondence between the second uniformity level and the second plurality of duty cycles,
wherein to identify the second plurality of duty cycles, the processor is configured to determine that the second plurality of duty cycles correspond to the second uniformity level in the listing, and
wherein to control the RF generator, the processor is configured to send a recipe signal having the second plurality of duty cycles to the RF generator.
17 . The controller of claim 16 , wherein to control the RF generator, the processor is configured to send a trigger signal to the RF generator after sending the recipe signal.
18 . The controller of claim 15 , wherein a number of the second plurality of states is unequal to a number of the first plurality of states.
19 . The method of claim 1 , wherein a number of the first plurality of duty cycles is different from a number of the second plurality of duty cycles.
20 . The controller of claim 15 , wherein a number of the first plurality of duty cycles is different from a number of the second plurality of duty cycles.