Systems and methods for reducing backside deposition and mitigating thickness changes at substrate edges
A substrate processing system for depositing film on a substrate includes a processing chamber defining a reaction volume and including a substrate support for supporting the substrate. A gas delivery system is configured to introduce process gas into the reaction volume of the processing chamber. A plasma generator is configured to selectively generate RF plasma in the reaction volume. A clamping system is configured to clamp the substrate to the substrate support during deposition of the film. A backside purging system is configured to supply a reactant gas to a backside edge of the substrate to purge the backside edge during the deposition of the film.
1. A substrate processing system for depositing film on a substrate, comprising:
a processing chamber defining a reaction volume and including a substrate support for supporting the substrate;
a gas delivery system configured to introduce process gas into the reaction volume of the processing chamber;
a plasma generator configured to selectively generate RF plasma in the reaction volume;
a clamping system configured to clamp the substrate to the substrate support during deposition of the film; and
a backside purging system configured to supply, as a purge gas, a reactant gas and not inert gas to a backside edge of the substrate to purge the backside edge during the deposition of the film and during the generation of the RF plasma in the reaction volume,
wherein, to supply the purge gas,
the backside purging system is configured to flow the purge gas at a rate greater than or equal to 150 sccm to purge the backside edge during the generation of the RF plasma,
the backside purging system is configured to provide molecular oxygen as the purge gas, and
the backside purging system is configured to provide the molecular oxygen as the purge gas to (i) inhibit at least one of plasma light-up and hollow cathode discharge signatures proximate the backside edge during the generation of the RF plasma in the reaction volume and (ii) inhibit parasitic power loss associated with the purge gas.
2. The substrate processing system of claim 1 , wherein the clamping system includes a vacuum clamping system to clamp the substrate to the substrate support using vacuum pressure.
3. The substrate processing system of claim 1 , wherein the film includes silicon dioxide.
4. The substrate processing system of claim 1 , wherein the film is deposited using atomic layer deposition.
5. The substrate processing system of claim 2 , wherein the rate is sufficient to move the substrate in the absence of the vacuum pressure.
6. The substrate processing system of claim 2 , wherein the vacuum clamping system includes:
a valve;
a cavity arranged on a substrate-facing surface of the substrate support, wherein the cavity is in fluid communication with the valve; and
a vacuum source in fluid communication with the valve.
7. The substrate processing system of claim 1 , wherein the backside purging system includes:
a valve;
a cavity arranged on a substrate-facing surface of the substrate support adjacent to an edge of the substrate, wherein the cavity is in fluid communication with the valve; and
a reactant gas source in fluid communication with the valve.
8. The substrate processing system of claim 1 , further comprising a controller configured to control the gas delivery system, the plasma generator, the clamping system, and the backside purging system during one or more atomic layer deposition cycles.