Thermally-stabilised temperature-dependant high strain electrostrictive actuator via Peltier energy extraction for high precision applications

摘要

In deep ultraviolet (DUV) and extreme ultraviolet (EUV) lithography, a deformable mirror (DM) is implemented in the projection lens for optical control. Actuation of the DM can be performed with an array of actuators on the back of the DM Each of these actuators are able to locally deform the surface of the mirror. Both the displacement and shape of the mirror can therefore be controlled The proposed system relates to electrostrictive actuators in particular, which operate via electrostriction. Electros diction is a property in which dielectric materials experience strain (material elongation) when exposed to an external electric field. The electrosnictive actuators therefore elongate in response to an applied external electric field, and deform the mirror into its desired shape. Electrostriction is desirable in this application because there is a tuneable field-strain sensitivity and low hysteresis. The field-strain relation is however very temperature dependant.