Lithography Machine Precision Temperature Control System Of Monitoring Subsystem

As is well known, the lithographic process is the kernel step of the microelectronicmanufacturing process, and the lithography machine is an important equipment whichdetermines the line width of the microcircuit pattern. In addition, the193nm lithographymachine has been established as one of the National Major Special Planning Projects.The exposure light source objective of lithography machine needs temperature controlultra-precisely and the error should be no more than±0.01℃, so that the imageaccuracyof lithography can be guaranteed. Therefore, the precision temperature control system isdesigned, which is used for lithography machines, with circulating water inside. Thisthesis focuses on the design of monitoring subsystem of the precision tempraturecontrol system, which is made up of four parts: the data acquisition of the controlledtargets, the bottom-communication carried out by PLC, the design of local HMImonitoring software and the design of remote PC monitoring software.Firstly, the overall structure of circuit and waterway of the temperature control isdiscussed in the thesis. The data of temperature control is collected from these sensors:Pt100temperature sensor which is the core sensor, level sensor, flow sensor, leakagedetection sensor, etc. When the data acquisition is completed, the system with PLC ascenter, starts to process the acquired information. And then the temperature controlarithmetic begins, carried out by the temperature controller. Meanwhile, actuators, suchas pump and electromagnetic valves, are operated by the system in order to controltemperature precisely.Secondly, the design of the lower computer modules in the monitoring subsystemis elaborated. The communication protocol between PLC’s232IF communicationmodule and the temperature controller is included and analysised, and then thecommunication programs between PLC and temperature controller are composed, andthe registers are distributed as well, which are used for storing bottom-information ofmonitoring.Thirdly, the local monitoring module, which is a part of the monitoring subsystem,is disscussed. It is TaiWai WV Company’s MT6000Serial HMI products and EB8000 configuration software that are adopted in the subsystem. According to thecommunication between PLC and HMI, the upper computer modules are built, whichare used for the local monitoring. As for the monitoring object, there areelectromagnetic valves, temperature profile, fault signal of alarm, history database andso on.Finally, in order to meet the needs of man-machine separation and remoteoperation during the producing and researching, the remote monitoring module isdesigned, which specially monitor the PID parameters and the failure events, and themain monitoring method uses double-buffering technology and ActiveX controlstechnique. Moreover, this module is written by VB6.0, and its communication link isbased on RS485and RS232protocols. From the above, the online testing isimplemented, which proved that the monitoring subsystem is effective.