US 2025/0102920 A1 · METHOD FOR HEATING AN OPTICAL ELEMENT, AND OPTICAL SYSTEM

Abstract

A method for heating an optical element in an optical system, such as in a microlithographic projection exposure system comprises using a thermal manipulator to introduce a heating power into the optical element to produce a thermally induced deformation. Before starting operation of the optical system in which useful light impinges on the optical element, the heating power is adjusted with respect to a desired state of the optical element in which a first optical aberration is at least partially compensated. After starting operation of the optical system, the heating power is regulated to the desired state depending on the heat load of the useful light impinging on the optical element. The heating power is regulated in such a way that the average temperature of the optical element remains constant up to a maximum deviation of 0.5 K.

Claims23

Dependent claims

A method of using a sector heater to heat an optical element in an optical system, the method comprising:

a) before impinging used light on the optical element during operation of the optical system, setting a heating power to be introduced into different sectors of the optical element by the sector heater with respect to a target state of the optical element to at least partially compensate for a first optical aberration;
and
b) when operating the system while the used light impinges on the optical element, controlling the heating power introduced into the different sectors of the optical element by the sector heater to achieve the target state based on:
i) a thermal load of the used light incident on the optical element;
and ii) an estimation of a wavefront effect of the optical system.

2 more elements

Dependencies are inferred from the claim text.

Method for heating an optical element, and optical system

Life of this patent

Method for heating an optical element, and optical system

Life of this patent

Abstract

Claims23