Particle generation suppressor by DC bias modulation
Methods for reducing particle generation in a processing chamber are disclosed. The methods generally include generating a plasma between a powered top electrode and a grounded bottom electrode, wherein the top electrode is parallel to the bottom electrode, and applying a constant zero DC bias voltage to the powered top electrode during a film deposition process to minimize the electrical potential difference between the powered top electrode and the plasma and/or the electrical potential difference between the grounded bottom electrode and the plasma.
1. A method for processing a substrate in a processing chamber, comprising:
generating a plasma between a first electrode and a second electrode of the processing chamber by applying a radio frequency (RF) power to the first electrode during a film deposition process, wherein the first electrode is disposed above the second electrode, and the second electrode is disposed above and opposing a substrate support having a substrate supporting surface; and
applying a constant zero DC bias voltage to the first electrode during the film deposition process.
2. The method of claim 1 , wherein the RF power is about 550 W or above.
3. The method of claim 1 , wherein the first electrode and the second electrode are separate from the substrate support by a gas distribution plate having a plurality of through holes.
4. The method of claim 1 , wherein the second electrode is electrically connected to ground.
5. The method of claim 1 , wherein the applying a constant zero DC bias voltage to the first electrode is controlled by a power controller coupled to a DC power supply.
6. The method of claim 1 , wherein the first electrode and/or the second electrode is coated with a protective layer comprising alumina or yttrium oxide.
7. A method for processing a substrate in a processing chamber, comprising:
generating a plasma between a first electrode and a second electrode by applying radio frequency (RF) power to the first electrode, wherein the first electrode is disposed above the second electrode, and the second electrode is disposed above and opposing a substrate support having a substrate supporting surface;
monitoring a DC bias voltage generated at the first electrode to obtain a DC bias feedback signal; and
controlling a DC bias voltage polarity at the first electrode based on the DC bias feedback signal by operating the first electrode with a constant zero DC bias voltage during a film deposition process.
8. The method of claim 7 , wherein the operating the first electrode with a constant zero DC bias voltage is performed by applying a zero DC bias voltage to the first electrode.
9. The method of claim 7 , wherein the operating the first electrode with a constant zero DC bias voltage is performed by directing a DC bias voltage from the first electrode to ground.
10. The method of claim 7 , wherein the first electrode and the bottom electrode are separate from the substrate support by a gas distribution plate having a plurality of through holes.