1 . A method of manufacturing a semiconductor wafer, the method comprising: performing a leak check on a semiconductor wafer processing tool that includes a process chamber having a process gas line that includes a mass flow controller (MFC), normally closed pneumatic valves including an upstream valve that is upstream of the MFC and a downstream valve that is downstream of the MFC, a pneumatic control line having a trunk, an upstream branch connected to deliver pneumatic pressure to the upstream valve, and a downstream branch connected to deliver pneumatic pressure to the downstream valve, an electrically actuated valve controlling pneumatic pressure through the trunk that is switchable between a closed position and an open position, and an electrically actuated relay controlling pneumatic pressure through the upstream branch; and in response to passing the leak check, performing processing on the semiconductor wafer using the semiconductor wafer processing tool; wherein the performing of the leak check includes: performing a leak check up to the downstream valve with the electrically actuated valve closed; and performing a leak check up to the upstream valve with the electrically actuated valve open and the electrically actuated relay open.
2 . The method of claim 1 wherein the process chamber is a deposition chamber and the processing on the semiconductor wafer performed using the semiconductor wafer processing tool includes depositing at least one material on the semiconductor wafer using the deposition chamber.
3 . The method of claim 2 wherein the deposition chamber is a chemical vapor deposition (CVD) chamber and the processing on the semiconductor wafer performed using the semiconductor wafer processing tool includes depositing titanium nitride (TiN) on the semiconductor wafer using the CVD chamber.
4 . The method of claim 3 wherein the depositing of TiN on the semiconductor wafer using the semiconductor wafer processing tool includes delivering a titanium-containing metalorganic compound to the CVD chamber using a bubbler system of the semiconductor wafer processing tool.
5 . The method of claim 1 wherein the performing of the leak check up to the downstream valve and the performing of the leak check up to the upstream valve each include: with a pressure sensor, measuring a pressure in the semiconductor wafer processing tool, the leak check being passed if the measured pressure does not exceed a threshold pressure.
6 . The method of claim 1 wherein the performing of the leak check up to the downstream valve and the performing of the leak check up to the upstream valve each includes: with a vacuum pump, drawing a vacuum in the semiconductor wafer processing tool for a first time interval and then stopping the drawing of the vacuum; and a second time interval after the stopping, measuring pressure in the semiconductor wafer processing tool using a pressure sensor; wherein the leak check is passed if the measured pressure does not exceed the threshold pressure.
7 . The method of claim 1 wherein the leak check is performed automatically using at least one electronic sensor.
8 . The method of claim 7 wherein the processing performed on the semiconductor wafer using the semiconductor wafer processing tool is performed with the electrically actuated valve open and the electrically actuated relay closed.
9 . The method of claim 7 wherein the at least one electronic sensor comprises a gas analyzer or gas sniffer sensor.
10 . A method of manufacturing a semiconductor wafer, the method comprising: performing a leak check on a semiconductor wafer processing tool that includes a process chamber and a plurality of process gas lines, each process gas line including a mass flow controller (MFC) and normally closed valves including an upstream valve that is upstream of the MFC and a downstream valve that is downstream of the MFC; and in response to passing the leak check, depositing at least one material on the semiconductor wafer using the semiconductor wafer processing tool; wherein the performing of the leak check includes: performing a leak check up to the downstream valves of the process gas lines with the upstream valves of the process gas lines closed and the downstream valves of the process gas lines closed; and performing a leak check up to the upstream valve of each the process gas line with the upstream valves of the of the process gas lines closed and with the downstream valve of the of the process gas line being leak checked open and the downstream valve of every other process gas line closed.
11 . The method of claim 10 wherein the semiconductor wafer processing tool is a chemical vapor deposition (CVD) tool, the process chamber is a CVD chamber, and the at least one material includes titanium nitride (TiN).
12 . The method of claim 11 wherein the depositing of TiN includes delivering tetrakis-(dimethylamido)titanium (TDMAT) to the CVD chamber using a bubbler system.
13 . The method of claim 10 wherein: the upstream and downstream valves of each process gas lines are pneumatic valves configured to be actuated together by pneumatic pressure delivered by a pneumatic control line for the process gas line that is controlled by an electrically actuated valve and in which the pneumatic control line includes a branch connected to deliver the pneumatic pressure only to the upstream valve and in which a relay controls the branch; the leak check up to the downstream valves of the process gas lines is performed with the electrically actuated valves of the process gas lines closed so that the upstream valves and the downstream valves of the process gas lines are closed; and the leak check up to the upstream valve of each process gas line is performed with (i) the electrically actuated valve of the process gas line being leak checked open and with the relay controlling the branch of the pneumatic control line of the process gas line being leak checked open and (ii) the electrically actuated valves of every other process gas line closed so that the upstream valves and the downstream valves of every other process gas line is closed.
14 . The method of claim 10 wherein the performing of the leak check up to the downstream valve and the performing of the leak check up to the upstream valve each include: with a pressure sensor, measuring a pressure in the semiconductor wafer processing tool; wherein the leak check is passed if the measured pressure does not exceed a threshold pressure.
15 . The method of claim 10 wherein the performing of the leak check up to the downstream valve and the performing of the leak check up to the upstream valve each includes: with a vacuum pump, drawing a vacuum on the semiconductor wafer processing tool for a first time interval and then stopping the drawing of the vacuum; and a second time interval after the stopping, measuring pressure in the semiconductor wafer processing tool using a pressure sensor; wherein the leak check is passed if the measured pressure does not exceed the threshold pressure.
16 . The method of claim 10 wherein the leak check is performed automatically using at least one electronic sensor and automated actuation of the upstream and downstream valves, and the processing performed on the semiconductor wafer using the semiconductor wafer processing tool is initiated automatically in response to passing the leak check.
17 . A gas delivery system for a semiconductor wafer processing tool, the gas delivery system comprising: a plurality of process gas lines each comprising a mass flow controller (MFC) and normally closed pneumatic valves including an upstream valve that is upstream of the MFC and a downstream valve that is downstream of the MFC; and a pneumatic valve controller including a pneumatic pressure inlet and, for each process gas line of the plurality of process gas lines: a pneumatic control line having a trunk receiving pneumatic pressure from the pneumatic pressure inlet and that branches into an upstream branch connected to deliver the pneumatic pressure to the upstream valve of the process gas line and a downstream branch connected to deliver the pneumatic pressure to the downstream valve of the process gas line; an electrically actuated valve controlling pneumatic pressure through the trunk that has closed and open positions; and an electrically actuated relay controlling pneumatic pressure through the upstream branch.
18 . The gas delivery system of claim 17 wherein the pneumatic valve controller further includes: an electronic processor programmed to control the electrically actuated valve and the electrically actuated relay of each process gas line to implement selectable modes including: a mode for leak checking up to the downstream valve of the process gas line in which the electrically actuated valve is closed; and a mode for leak checking up to the upstream valve of the process gas line in which the electrically actuated valve is open and the electrically actuated relay is open.
19 . The gas delivery system of claim 18 wherein the electronic processor is programmed to control the electrically actuated valve and the electrically actuated relay of each process gas line to implement the selectable modes further including: an operational mode in which the electrically actuated valve is open and the electrically actuated relay is closed.
20 . The gas delivery system of claim 17 further comprising a gas mixing manifold, each process gas line of the plurality of process gas lines feeding into the gas mixing manifold.
