Systems and methods for controlling a voltage waveform at a substrate during plasma processing
Systems and methods for controlling a voltage waveform at a substrate during plasma processing include applying a shaped pulse bias waveform to a substrate support, the substrate support including an electrostatic chuck, a chucking pole, a substrate support surface and an electrode separated from the substrate support surface by a layer of dielectric material. The systems and methods further include capturing a voltage representative of a voltage at a substrate positioned on the substrate support surface and iteratively adjusting the shaped pulse bias waveform based on the captured signal. In a plasma processing system a thickness and a composition of a layer of dielectric material separating the electrode and the substrate support surface can be selected such that a capacitance between the electrode and the substrate support surface is at least an order of magnitude greater than a capacitance between the substrate support surface and a plasma surface.
1. A plasma processing system, comprising:
a substrate support defining a surface for supporting a substrate to be processed, the substrate support including an electrostatic chuck comprising a chucking pole, and an electrode, wherein the electrode and the chucking pole are disposed in a layer of dielectric material and are separated from the substrate support surface by respective portions of the layer of dielectric material;
a plasma, disposed above the substrate support surface;
a sensor capturing a signal representative of a voltage at a substrate positioned
on the substrate support surface;
a bias supply providing a shaped pulse bias waveform to the chucking pole;
a controller receiving the captured signal from the sensor and generating a control signal to be communicated to the bias supply to adjust the shaped pulse bias waveform based on the captured signal; and
wherein the chucking pole is located in the layer of dielectric material such that a thickness of a portion of the layer of dielectric material between the chucking pole and the substrate support surface is at least ten times less than a thickness of a portion of the layer of dielectric material between the electrode and the substrate support surface.
2. The plasma processing system of claim 1 , further comprising a coupling circuit for coupling the shaped pulse bias waveform to the chucking pole.
3. The plasma processing system of claim 1 , wherein a clamping voltage is further applied to the chucking pole.
4. The plasma processing system of claim 3 , further comprising a coupling circuit for coupling the clamping voltage to the chucking pole.
5. The plasma processing system of claim 3 , wherein the clamping voltage is isolated with a large resistor.
6. The plasma processing system of claim 1 , wherein the dielectric material comprises aluminum nitride.
7. The plasma processing system of claim 1 , wherein the chucking pole is located in the layer of dielectric material such that a thickness of a portion of the layer of dielectric material between the chucking pole and the substrate support surface is 0.3 mm or less when a thickness of a portion of the layer of dielectric material between the electrode and the substrate support surface is at least 3 mm.
8. A plasma processing system, comprising:
a substrate support defining a surface for supporting a substrate to be processed, the substrate support including an electrostatic chuck comprising a chucking pole, and an electrode, wherein the electrode and the chucking pole are disposed in a layer of dielectric material and are separated from the substrate support surface by respective portions of the layer of dielectric material;
a plasma, disposed above the substrate support surface; and
a shaped pulse bias waveform generator to apply a shaped pulse bias waveform to the chucking pole,
wherein the chucking pole is located in the layer of dielectric material such that a thickness of a portion of the layer of dielectric material between the chucking pole and the substrate support surface is at least ten times less than a thickness of a portion of the layer of dielectric material between the electrode and the substrate support surface.
9. The plasma processing system of claim 8 , wherein the dielectric layer comprises aluminum nitride.
10. The plasma processing system of claim 8 , wherein a clamping voltage is further applied to the chucking pole.
11. The plasma processing system of claim 10 , wherein the clamping voltage is isolated with a large resistor.
12. The plasma processing system of claim 8 , comprising a coupling circuit for coupling the shaped pulse bias waveform and a clamping voltage to the substrate support.
13. The plasma processing system of claim 8 , wherein the chucking pole is located in the layer of dielectric material such that a thickness of a portion of the layer of dielectric material between the chucking pole and the substrate support surface is 0.3 mm or less when a thickness of a portion of the layer of dielectric material between the electrode and the substrate support surface is at least 3 mm.