Adaptive Mirror Mediator Layer Segmentation
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Solution Overview
Problem
Conventional adaptive mirrors in microlithographic projection exposure apparatuses face challenges in accurately correcting imaging aberrations due to insufficient deformation profile realization and thermal issues arising from the mediator layer's high electrical sheet resistance, which compromises between rapid reaction capability and thermal deformation avoidance.
Innovation Solution
A structured mediator layer with mutually electrically insulated regions is used, allowing only local electrical connections between adjacent electrodes, reducing remote interaction and achieving a polynomial voltage profile, thereby improving deformation profile approximation and reducing thermal problems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a continuous mediator layer with high electrical sheet resistance is used, then thermal deformation is avoided, but the reaction capability is slowed down
Solution Approach 1:
The mediator layer is segmented into multiple mutually electrically insulated regions, each associated with specific electrodes. This segmentation allows low resistance paths for rapid voltage distribution within each region while maintaining high resistance between regions to prevent thermal coupling, thus resolving the contradiction between reaction speed and thermal stability.
Solution Approach 2:
Different regions of the mediator layer are assigned different electrical properties: within each region, the mediator layer provides low resistance for fast voltage equalization, while between regions, it provides high resistance to isolate thermal effects. This local differentiation of electrical properties simultaneously optimizes both response speed and thermal performance.
2Manufacturing precision
If a continuous mediator layer is used, then potential distribution is simplified, but deformation profile precision is insufficient due to remote interaction between electrodes
Solution Approach 1:
The mediator layer is divided into discrete, electrically insulated regions corresponding to individual electrodes. This segmentation eliminates remote interaction between non-adjacent electrodes by blocking current paths through the mediator layer, thereby achieving precise local voltage control and accurate deformation profiles.
Solution Approach 2:
The mediator layer acts as an intermediary that selectively conducts voltage between adjacent electrodes while blocking voltage transmission between non-adjacent electrodes. This selective mediation enables precise control of the deformation profile by allowing only local electrical interactions.
3Temperature
If high electrical sheet resistance is used in the mediator layer, then thermal issues are reduced, but the voltage distribution becomes non-uniform and reaction capability decreases
Solution Approach 1:
By segmenting the mediator layer into isolated regions, the patent allows each region to maintain high resistance for thermal isolation while ensuring low resistance pathways within each region for rapid voltage distribution. This segmentation resolves the contradiction by making the resistance property spatially dependent rather than uniform.
Solution Approach 2:
The mediator layer exhibits locally optimized electrical properties: high resistance between regions for thermal management and low resistance within regions for fast voltage equalization. This local quality differentiation enables simultaneous optimization of thermal performance and response speed.
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
This approach enables more accurate correction of imaging aberrations and reduces thermal issues by enhancing the adaptive mirror's reaction capability and deformation profile precision, while minimizing unwanted thermal deformations.
Implementation Method 1
a piezoelectric layer (86), which is produced from lead zirconate titanate (Pb(Zr,Ti)O3, PZT) in the example. Electrode arrangements are respectively situated above and below the piezoelectric layer (86), by way of which electrode arrangements an electric field for producing a locally variable deformation is able to be applied to the mirror (80)
Implementation Method 2
Said mediator layer (87) serves to 'mediate' between the electrodes (90) in terms of potential, wherein it has only low electrical conductivity, with the consequence that a potential difference existing between adjacent electrodes (90) is dropped substantially across the mediator layer (87)
Data Source
AI summary
A microlithographic projection exposure mirror has a mirror substrate (12, 32), a reflection layer system (21, 41) for reflecting electromagnetic radiation that is incident on the mirror's optical effective surface, and at least one piezoelectric layer (16, 36), which is arranged between the mirror substrate and the reflection layer system and to which an electric field for producing a locally variable deformation is applied by a first electrode arrangement situated on the side of the piezoelectric layer facing the reflection layer system, and by a second electrode arrangement situated on the side of the piezoelectric layer facing the mirror substrate. One of the electrode arrangements is assigned a mediator layer (17, 37, 51, 52, 53, 71) for setting an at least regionally continuous profile of the electrical potential along the respective electrode arrangement. The mediator layer has at least two mutually electrically insulated regions (17a, 17b, 17c, . . . ; 37a, 37b, 37c, . . . ).