Lithographic Illumination Source Pixel Group Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithographic systems face challenges in optimizing illumination conditions to achieve precise feature printing, particularly in enhancing depth of focus and critical dimension uniformity, especially at low k1 values where image calculations deviate from printed substrate results.
Innovation Solution
The method involves dividing the illumination source into pixel groups, iteratively calculating lithographic metrics, and adjusting the illumination shape based on these calculations to optimize the illumination configuration for improved precision and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional full circular illumination is used, then the illumination system is simple and easy to operate, but the critical dimension uniformity and depth of focus are insufficient
Solution Approach 1:
The illumination source is divided into multiple pixel groups that can be independently controlled and adjusted. Each pixel group represents a discrete region of the illumination source that can be individually optimized, allowing complex illumination patterns to be built from simpler modular units. This segmentation enables precise control over the illumination distribution while maintaining manageable system complexity.
Solution Approach 2:
The illumination shape is made dynamically adjustable through iterative modification of pixel group states. The system can transition between different illumination configurations by changing which pixel groups are active, allowing the illumination pattern to be optimized for different patterning requirements without requiring multiple fixed illumination systems.
2Manufacturing precision
If iterative calculation and adjustment of illumination shape is performed, then the lithographic metric and critical dimension uniformity improve, but the computation time and process complexity increase
Solution Approach 1:
The illumination source is pre-divided into pixel groups with defined states before the actual patterning process. This preliminary structuring allows for systematic iterative optimization where only the necessary pixel group configurations need to be calculated and adjusted, rather than optimizing the entire illumination field from scratch each time.
Solution Approach 2:
The system uses iterative calculation of lithographic metrics based on changes in pixel group states to provide feedback for optimizing the illumination shape. Each iteration evaluates the effect of pixel group modifications on the lithographic outcome and adjusts the illumination configuration accordingly, converging toward an optimal solution through repeated measurement and adjustment.
3Manufacturing precision
If the illumination shape is optimized for specific patterns, then the printing precision improves, but the adaptability to different pitches and patterns decreases
Solution Approach 1:
The pixel group-based illumination control system provides universal adaptability to different patterning requirements. The same set of pixel groups can be configured to produce various illumination shapes suitable for different pitch ranges and pattern types, making the system multi-functional without requiring separate optimization for each specific case.
Solution Approach 2:
The system optimizes printing precision by changing the state parameters of pixel groups (which are active or inactive, and their intensity levels) rather than changing the fundamental structure of the illumination system. These parameter adjustments allow the same physical illumination system to adapt to different patterning needs through software-controlled modifications to the pixel group configuration.
Data Source
AI summary
A method for configuring an illumination source of a lithographic apparatus is presented. The method includes dividing the illumination source into pixel groups, each pixel group including one or more illumination source points; selecting an illumination shape to expose a pattern, the illumination shape formed with at least one pixel group; iteratively calculating a lithographic metric as a result of a change of state of a pixel group in the illumination source, the change of the state of the pixel group creating a modified illumination shape; and adjusting the illumination shape based on the iterative results of calculations.