Adaptive Optical Element Temperature Compensation
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Solution Overview
Problem
Piezoelectric or electrostrictive adaptive optical elements in microlithography face inaccuracies in surface shape corrections due to temperature variations in the actuator material, leading to inaccuracies in wavefront aberration corrections.
Innovation Solution
An adaptive optical element with a dielectric medium that is deformable via an electric field, incorporating a measuring electrode with temperature-dependent resistance, directly assembled with the dielectric medium to accurately measure temperature and control length expansion, thereby improving surface shape correction accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If piezoelectric or electrostrictive manipulators are used to change the shape of the optical surface, then the ability to correct wavefront errors is improved, but temperature variations in the actuator material cause inaccuracies in surface shape corrections
Solution Approach 1:
A measuring electrode with temperature-dependent resistance is integrated directly into the dielectric medium to provide real-time temperature feedback. This temperature information is used to compensate for thermal expansion effects on the manipulator, enabling accurate surface shape corrections despite temperature variations. The feedback loop continuously monitors and corrects for temperature-induced errors.
Solution Approach 2:
The measuring electrode acts as an intermediary element embedded within the dielectric medium. It indirectly measures the temperature of the actuator material through its temperature-dependent resistance, providing a means to monitor and compensate for thermal effects without directly contacting or interfering with the piezoelectric/electrostrictive material's primary function.
2Measurement precision
If the measuring electrode is arranged in direct assemblage with the dielectric medium, then temperature measurement precision is improved, but the complexity of the manipulator structure increases
Solution Approach 1:
The measuring electrode is merged directly with the dielectric medium through direct assemblage, eliminating the need for separate mounting structures, adhesives, or intermediate layers. This integration achieves high temperature measurement precision while minimizing structural complexity by combining two functional elements into a unified assembly.
Solution Approach 2:
The dielectric medium serves multiple functions: it provides the electrostrictive actuation function and simultaneously serves as the mounting substrate for the measuring electrode. This multi-functionality reduces the need for additional structural components, thereby limiting the increase in device complexity despite the enhanced measurement capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The direct assembly of the measuring electrode with the dielectric medium allows for precise temperature measurement and control, enhancing the accuracy of surface shape corrections and reducing inaccuracies caused by temperature variations.
Implementation Method 1
The functionality of such manipulators is generally based on the deformation of a dielectric medium by the application of an electric field
Implementation Method 2
piezoelectric or electrostrictive manipulators for the purposes of actuating the optical surface
Implementation Method 3
a measuring electrode which serves for measuring temperature, is arranged in a direct assemblage with the dielectric medium, and has a temperature-dependent resistance
Data Source
AI summary
An adaptive optical element for microlithography comprises at least one manipulator for changing the shape of an optical surface of the optical element. The manipulator comprises a dielectric medium which is deformable via an electric field, work electrodes for generating the electric field in the dielectric medium, and a measuring electrode for measuring temperature. The measuring electrode is arranged in a direct assemblage with the dielectric medium. The measuring electrode has a temperature-dependent resistance.