Clean isolation valve for reduced dead volume
Gas distribution apparatus, processing chambers and methods using a dead volume-free valve are described. The valve has a first inlet line with upstream and downstream ends and a second inlet line with a downstream end that connects to the first inlet line. A sealing surface at the downstream end of the second inlet line separates the first inlet line from the second inlet line preventing fluid communication between the first inlet line and the second inlet line.
1. A processing method comprising: flowing a first gas through a first inlet line of a dead volume-free valve into a processing chamber, a spacer within an opening in a top of the processing chamber, wherein the spacer is positioned around a gas distribution plate within the opening in the top of the processing chamber, the dead volume-free valve comprising: the first inlet line having an upstream end and a downstream end defining a length of the first inlet line, a second inlet line having an upstream end and a downstream end defining a length of the second inlet line, the downstream end of the inlet line connecting with the first inlet line along the length of the first inlet line, and a sealing surface at the downstream end of the second inlet line, the sealing surface configured to separate the first inlet line and the second inlet line to prevent fluid communication between the first inlet line and the second inlet line; and flowing a second gas through the second inlet line of the dead volume-free valve into the processing chamber, wherein the first gas does not flow into the second inlet line and switching between the first gas and second gas does not include a purge step to clear the valve of residual gas.
2. The processing method of claim 1 , further comprising igniting a plasma from one or more of the first gas or second gas in a remote plasma source positioned downstream of the dead volume-free valve.
3. The processing method of claim 1 , wherein the remote plasma source is positioned between the downstream end of the first inlet line and the gas distribution plate.
4. The processing method of claim 3 , further comprising a gas manifold between the downstream end of the first inlet line and the remote plasma source, the gas manifold configured to split the gas flow exiting the dead volume-free valve to a plurality of process chambers.
5. The processing method of claim 1 , wherein the second gas moves the sealing surface to an open position when the second gas flowing through the second inlet line exceeds a predetermined pressure.
6. The processing method of claim 5 , wherein the sealing surface in the open position allows movement of a fluid through the second inlet line to enter the first inlet line and prevents fluid from the first inlet line from entering the downstream end of the second inlet line.
7. The processing method of claim 1 , wherein the sealing surface moves to a closed position when there is no gas flow in the second inlet line or a pressure in the second line is below a predetermined threshold.
8. A processing platform comprising: a central transfer station comprising a robot configured to: flow a first gas through a first inlet line of a dead volume-free valve into a processing chamber, a spacer within an opening in a top of the processing chamber, wherein the spacer is positioned around a gas distribution plate within the opening in the top of the processing chamber, the dead volume-free valve comprising: the first inlet line having an upstream end and a downstream end defining a length of the first inlet line, a second inlet line having an upstream end and a downstream end defining a length of the second inlet line, the downstream end of the inlet line connecting with the first inlet line along the length of the first inlet line, and a sealing surface at the downstream end of the second inlet line, the sealing surface configured to separate the first inlet line and the second inlet line to prevent fluid communication between the first inlet line and the second inlet line; and flow a second gas through the second inlet line of the dead volume-free valve into the processing chamber, wherein the first gas does not flow into the second inlet line and switching between the first gas and second gas does not include a purge step to clear the valve of residual gas.
9. The processing platform of claim 8 , further comprising a substrate support inside the processing chamber.
10. The processing platform of claim 9 , wherein the substrate support has a support surface spaced a distance from a front surface of the gas distribution plate.
11. The processing platform of claim 8 , wherein the gas distribution plate comprises a showerhead.