Study of an optimization design method about vibration damping for an electron beam system

This paper proposes an optimization design method of vibration damping for an electron beam system. It realizes low cost and highly precise electron beam system. Semiconductor devices which are smaller and thinner are required by growing of smartphones and tablet PCs, However, semiconductor device factories have an issue that productivity is decreased by disturbance vibration. Especially, it is difficult to compensate both floor vibration and equipment's inner vibration. Furthermore, an active damper that does not make magnet field is required, because reducing distortion of deflection of electron beam is very important for an electron beam equipment. In such background, this paper proposes a design method for an active damping by using a state feedback controller with an estimator of column vibration. The proposed controller has negative feedback of chamber state and estimated electron beam column state. In addition, this paper proposes a design method for adapting to an environment of a semiconductor device factory by including variable parameters into the state feedback controller. Finally, this paper describes an experimental result of the design method of vibration damping.