The DELTA™ III Flow Ratio Controller divides and controls mixed process gas flows to three chambers or zones within a process chamber at proportions specified by the user to optimize process uniformity and repeatability. Available with EtherCAT® or DeviceNet™ communications, this device provides the latest in gas flow ratio measurement and control technology.
The DELTA III, three channel ratio controller provides a needed “knob” to tune process gas flows over the substrate surface or gas dispersion head to help achieve these uniformities. The DELTA III ratio controller provides closed loop control over the flow proportion that is not available with typical metering valve or flow orifice setups that have often been used. The DELTA ratio controllers provide the added advantage of tuning the process from the tool controller as opposed to manual valve adjustment necessary with metering valve and manual changeout which is impractical with fixed flow orifices.
The DELTA III has a wide dynamic ratio control range and fast development of chamber flow while being adaptive to different tool and process conditions. MKS has developed a unique patent pending ratio control logic enabling rapid ratio and flow response times. This control logic enables the total input flow to be split with channel flows ranging from 2 to 100% of the channel Full Scale for measurement and control purposes. The total of all channel flows shall be split in such a way that their sum equals 100%. For example the flows may be split to 10, 20, 30 and 50% of total flow input going to channels Q1, Q2, and Q3, respectively. The dynamic control also allows for individual channels to be given 0% set points which closes the valve, effectively closing off flow to this output.
The DELTA’s diagnostic feature allows the user to check the DELTA’s performance in-situ, lowering costs through reduced removal of No Problem Found devices. This feature is enabled through a web browser utility accessed through the device’s Ethernet port. This utility uses a standard web browser and requires no special software. The diagnostic input includes the ability to control the device locally, operate the device, open and close valves along with collecting and saving data for later analysis.