Precise positioning control with double feedback loop for ultralarge scale integrated manufacturing machine

Abstract

This article presents a new positioning control system for ultralarge scale integrated (ULSI) circuit manufacturing machines. Both accuracy and high speed are required in the positioning control of ULSI manufacturing. Two major problems exist in the precise positioning control: mechanical resonance and steady state error induced by solid friction. The proposed control system utilizes H2 control to compensate for the mechanical resonance, and an integral action was combined with the H2 control in order to compensate for the steady state error. The proposed control system is composed of a double feedback control loop in which the inner control loop is the H2 controller, and the outer control loop is the integral action controller. A desired position is input to the integral action controller, and then the output signal of the integral action controller becomes the desired value of the H2 controller. In the controller design stage of the proposed control system, the H2 control gain and the integral action gain can be chosen independently. The validity of the proposed control system has been confirmed by the simulation and experimental results. The response was converged quickly to the sensor resolution of 50 nm with less vibration.