Software Design Of Dual-stage Based On Real-time Operating System Vxworks

As the key subsystem of lithography, dual-stage contains two wafer stages and onereticle stage. The wafer stage located in measurement zone will load, unload wafer anddo some measurement job. The one located in exposure area will synchronize waferstage, reticle stage, exposure system and slit system to exposure wafer. The exchangesystem is in charge of switching two wafer stages. Its control system adopts the mode ofupper-and-lower computer.IPC(industrial personal computer),as the lower computer, itcontrols running of the whole system and adopts embedded RTOS(real-time operatingsystem)VxWorks.A man-machine interface runs on PC. It sends command and data toIPC, gets some important parameters. This paper focuses on the lower computer.Firstly, this paper carries on a detailed plan on how the dual-stage system works,namely a process to turn a wafer to a chip. To be more specific, it contains what thewafer stage will do in measurement and exposure area, how to exchange two stages,how to synchronize four subsystems to exposure silicon and so on.Secondly, IPC adopts VxWorks as its operating system.This paper analyzes thekernel structure of VxWorks to get to know how to program on it. The IDE of VxWorksis Tornado2.2.This paper tells how it works and how to build debugging environment.To meet the need of real-time and reliability, it provides some ways to improve thesequalities.Thirdly, this paper builds network communication between upper and lowercomputer. To improve reliability, communication protocol is made.The information ispacked into frame which can be analyzed by both upper and lower computer. In order toreceive information timely, buffer queue is built to buffer all commands. In the end, anetwork communication experiment is designed to prove real-time quality andreliability.Finally, this paper carries on overall software design of dual-stage based on thefrontal knowledge. The design includes: software structure, tasks about to be spawn,task function, ways to communicate between tasks, program flow diagram and so on. Inthe end, single axis experimental table is carried on to test the validity and reliability ofsoftware design.