Design And Optimization Of VxWorks Software For Dual Wafer Stage

Wafer stage control system which control the wafer stage movement and exposureprocess, is important part of lithography system. IPC System works with the VxWorkssystems, using Network communication with the PC system and VME buscommunication with the following boards.Firstly, the work processes of the Wafer Stage system,which needs14steps isplanned. The stage in the measurement sector finish the loading and unloading the wafer,the position measurement of wafer stage; the stage in the exposure sector finish thestepper and scan with the help of Illuminating System, Reticle Control System, Off-axisAlignment System, Coaxial Alignment System and Slit Unit.Then, the architecture of the main PowerPC board in IPC System is studied and theBSP of VxWorks is configured. According to the PowerPC board, the VME bus drivers,network drivers and Flash file system drivers are provided to realize VME bus read andwrite,VME interrupts, network programming and Flash File System reading.Secondly, the software function modules are designed which contain Networkcommunication module, serial communication module, task scheduling module, VMEreader module, parameter setting module and error handling module. On the basis of thefunctional module, the VxWorks software system is divided into four modes: runningmode, test mode, simulation animation mode, error handling mode. And we details thenetwork communication program and VME interrupt service program.Finally, the real-time optimization processing are taken to improve the stability andthe speed of the network transmission. After using Zbuf zero-copy method and one kindof network analysis algorithm in network communication, the network communicationspeed and stability has been greatly improved. Also VxWorks memory planning andFlash file system provides the basis for large trajectory data processing. Buildexperimental environment of debugging motion station to verify the stability and real-time of the software system, and achieve the control precision requirements.