Methods to eliminate “M-shape” etch rate profile in inductively coupled plasma reactor
An inductively-coupled plasma processing chamber has a chamber with a ceiling. A first and second antenna are placed adjacent to the ceiling. The first antenna is concentric to the second antenna. A plasma source power supply is coupled to the first and second antenna. The plasma source power supply generates a first RF power to the first antenna, and a second RF power to the second antenna. A substrate support disposed within the chamber. The size of the first antenna and a distance between the substrate support are such that the etch rate of the substrate on the substrate support is substantially uniform.
1. An inductively coupled plasma reactor for processing a 300 mm substrate comprising:
a chamber having a ceiling;
a first outer antenna having a first solenoid coil and a second inner antenna having a second solenoid coil adjacent to the ceiling wherein the first outer antenna and the second inner antenna are physically separated from each other, the first outer antenna is concentric with the second inner antenna, and said first solenoid coil has a diameter of at least 17″;
a plasma source power supply coupled to the first and second antenna; and
a substrate support disposed within the chamber a distance of at least 6″ from said ceiling, wherein a size of the first outer antenna and a distance between the substrate support and the ceiling are such that an etch rate of the 300 mm substrate on the substrate support is substantially uniform without an M shape profile.
2. The apparatus of claim 1 wherein the diameter of the first solenoid coil is greater than the diameter of the second solenoid coil.
3. The apparatus of claim 1 wherein the etch rate of an inner region of the substrate is substantially dependent on the size of the first outer antenna.
4. The apparatus of claim 1 wherein the etch rate of an outer region of the substrate is substantially dependent on the distance between the substrate support and the ceiling.
5. The apparatus of claim 1 wherein the plasma source power supply further comprises:
a RF power supply; and
an impedance match network coupled to the RF power supply, wherein the impedance match network comprises a first and a second RF output having differentially adjustable power levels, the first RF output connected to the first outer antenna, the second RF output connected to the second inner antenna.
6. The apparatus of claim 5 wherein the impedance match network generates a first RF power level to the first outer antenna, and a RF second power level to the second inner antenna, wherein respective RF power levels applied to the first outer antenna and the second inner antenna are differentially adjustable to control radial distribution of an applied RF field from the first outer antenna and the second inner antenna.
7. An inductively-coupled plasma processing chamber comprising:
a chamber having a ceiling;
a first and second antenna adjacent to the ceiling, the first antenna concentric to the second antenna, wherein the first antenna and the second antenna are physically separated from each other;
a substrate support disposed in the chamber for supporting a 300 mm substrate;
means for supplying a first RF power to said first antenna and a second RF power to said second antenna; and
wherein the ceiling is separated from said substrate support by a distance and wherein said distance is adjustable, wherein the first antenna includes a first solenoid coil having a modifiable diameter, and the second antenna includes a second solenoid coil, the modifiable diameter of the first solenoid coil is greater than a diameter of the second solenoid coil, the modifiable diameter of the first solenoid coil is at least 17″, and wherein the distance between the substrate support and the ceiling is at least 6″, and the etch rate of a 300 mm wafer on the substrate support is uniform without an M shaped profile.