Design And Test Analysis Of The Lithography Active Vibration Isolation System

Improving the positioning precision of the lithography machine was the maindirection of lithography research. The higher the motion precision of the lithographymachine was, the higher the requirement of the environment was. But the interferenceof the ambient vibration and the vibration generated in working would impact themotion precision of lithography. Thus it needed to take vibration isolation. Because theprevious passive vibration isolation had poor vibration isolation effect on the1-100Hzlow frequency and active vibration isolation had good vibration isolation effect on lowfrequency, it was a must for lithography tool should use active vibration isolation.Firstly, this paper reviewed the development present situation of vibration isolationtechnology at home and abroad. the developing present situation of vibration isolationtechnology of the passive vibration isolation, the semi-active vibration isolation andactive vibration isolation were analyzed. the advantages and disadvantages of threekinds of isolation techniques were summarized. Comparing with the former twotechniques, the active vibration isolation involved by outside power and can isolate low-frequency vibration interference. So the active vibration isolation was the main studyingtrend of vibration isolation. Combining the working characteristics of the lithographywith the performance requirement of active vibration isolation, the paper took triple-aircushion vibration as shock absorber for vibration isolation platform of lithography tool,which was the overall architecture. And the working principle of air cushion isolation,actuators and sensors were briefly introduced.In order to analyze active vibration isolation performance of the lithography, ittook use of rigid body momentum equation to deduce six degrees of freedom dynamicmodel of active vibration isolation of the lithography. Due to its multiple inputs andoutputs dynamic model, it took modal control to decouple the model in order to simplifythe controller design. As a result, the dynamic model is simplified for single input andsingle output model. And then it adopted the position feedback and speed feedbackcontrol as control method of its active vibration isolation. After the analysis of alleffects that the various control parameters had on the active vibration isolation control,the author or the designer completed the entire controller design and simulationverification.Then, starting with the lithography active vibration isolation control card,the activevibration isolation control card was designed combined with the overall architecture ofactive vibration isolation of the lithography. And the hardware design circuit wasintroduced in detail.Because the hardware control card used the soft core of NIOS II ofthe FPGA, its soft core was configurated in QSYS software. Finally, the designer wrote lithography vibration testing interface based onLabVIEW software. the main functional modules were introduced.Then the verticalvibration was basically tested when the lithography was working on the vibrationisolation platform.