Illumination Optical Unit Imaging Quality Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current projection exposure apparatuses for microlithography face challenges in optimizing illumination settings to improve imaging quality in the image field, as existing methods focus primarily on pupil dimensions and object field properties without effectively addressing imaging variables in the image field.
Innovation Solution
A method for setting an illumination setting using a multiplicity of individual mirrors in a facet mirror system, with a controllable correction device and adjustable elements to influence transmission and angle-of-incidence distribution, allowing for precise optimization of imaging variables in the image field by varying illumination channels and using correction elements like filters or stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional illumination settings are used focusing on pupil dimensions, then the illumination optical unit is simpler to operate, but the imaging quality in the image field cannot be optimized
Solution Approach 1:
The patent implements dynamic illumination setting adjustment by varying the illumination channels formed by the facet mirrors. The system can dynamically adapt the illumination configuration based on the specific imaging requirements, allowing optimization of imaging variables such as critical dimension variation and telecentricity while maintaining operational flexibility
Solution Approach 2:
The patent changes physical parameters of the illumination system by adjusting the transmission characteristics through correction elements and varying the angle-of-incidence distribution. This allows precise control of imaging variables including critical dimension variation and projection aberrations without fundamentally changing the system architecture
2Manufacturing precision
If more illumination channels are used to improve imaging variables, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The patent segments the illumination system into multiple independent facet mirrors with individual mirrors that can be uniquely assigned to form different illumination channels. This segmentation allows selective activation of specific channels to optimize imaging variables like critical dimension variation while maintaining a manageable system structure
Solution Approach 2:
The facet mirror system serves multiple functions simultaneously - it acts as both the illumination element and the channel-forming component. The same mirrors that define the illumination geometry also control the angle-of-incidence distribution, eliminating the need for separate components and reducing overall device complexity
3Manufacturing precision
If correction elements are added to influence transmission, then the imaging quality optimizes, but the ease of manufacture decreases
Solution Approach 1:
The patent merges the correction function with the existing facet mirror system by integrating correction elements that can be selectively positioned in the beam path. This combination allows correction of projection aberrations while utilizing the existing structural framework, thereby reducing the need for entirely separate correction systems
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 enhances the quality of the illumination optical unit and projection exposure apparatus by optimizing imaging variables such as critical dimension variation, projection aberrations, and telecentricity, leading to improved microstructured or nanostructured component production with increased integration density.
Implementation Method 1
a first facet mirror comprising a multiplicity of individual mirrors, a second facet mirror comprising a multiplicity of individual mirrors, wherein the second facet mirror is disposed downstream of the first facet mirror in the beam path
Implementation Method 2
at least one mechanism for varying the illumination setting, wherein the at least one mechanism for varying the illumination setting comprises at least one controllable correction device which includes a multiplicity of adjustable correction elements for influencing the transmission
Data Source
AI summary
Method for setting an illumination setting in an illumination optical unit comprising at least one controllable correction device, which includes a multiplicity of adjustable correction elements for influencing the transmission, wherein the illumination setting is varied for adapting a predetermined imaging parameter in the region of an image field.