Substrate Measurement Recipe Selection for Overlay Error Precision
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Solution Overview
Problem
In lithographic processes, existing methods lack consistency in substrate measurement recipes, leading to inaccuracies and inefficiencies in overlay error measurement across different areas of a substrate, which affects the precision and accuracy of device fabrication.
Innovation Solution
A method is developed to determine recipe consistency within subsets of substrate measurement recipes based on values obtained from measuring or simulating diffracted radiation, selecting a recipe that minimizes differences and ensures robustness to process variations, using parameters like wavelength, polarization, and angle of incidence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple substrate measurement recipes are used to measure overlay errors across different areas, then measurement coverage is improved, but measurement precision deteriorates due to recipe inconsistency
Solution Approach 1:
The patent changes the parameters of substrate measurement recipes (such as illumination conditions, measurement targets, or processing parameters) to create a set of recipes that are optimized for different areas of the substrate. By systematically varying these parameters, the system achieves both broad coverage and consistent precision across all measurement areas.
Solution Approach 2:
The patent divides the substrate measurement process into multiple segments, each handled by a specific measurement recipe optimized for particular areas. This segmentation allows each recipe to be tuned for optimal performance in its designated region while maintaining overall consistency through coordinated parameter selection.
2Measurement precision
If substrate measurement recipes are optimized for specific areas, then measurement accuracy is improved, but device complexity increases due to multiple recipes
Solution Approach 1:
The patent creates a universal substrate measurement recipe system where a set of recipes can be applied across multiple areas and conditions. Each recipe is designed to be multi-functional, handling various measurement scenarios while following a unified framework that reduces overall system complexity despite the presence of multiple specialized recipes.
Solution Approach 2:
Instead of creating entirely separate measurement systems for different areas, the patent uses parameter changes within a unified recipe structure. This approach allows area-specific optimization while maintaining a single, manageable recipe management system, thereby reducing device complexity.
3Ease of operation
If conventional substrate measurement recipes are used, then ease of operation is maintained, but manufacturing precision deteriorates due to process-induced asymmetry
Solution Approach 1:
The patent incorporates feedback mechanisms where measurement results from preliminary recipes inform the selection or adjustment of subsequent recipes. This feedback loop allows the system to automatically compensate for process-induced asymmetries while maintaining ease of operation through automated recipe selection rather than manual intervention.
Solution Approach 2:
The patent adjusts measurement parameters based on detected process variations and asymmetries. By dynamically changing parameters such as illumination angle, wavelength, or target selection based on measured conditions, the system maintains high precision without complicating the operator's workflow, as these changes are automatically managed.
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 accuracy and precision of overlay error measurements by identifying consistent and robust substrate measurement recipes, reducing process-induced asymmetry and improving the overall reliability of device fabrication processes.
Implementation Method 1
obtaining the values of the characteristic by measuring or simulating diffracted radiation from the areas
Data Source
AI summary
A method including: determining recipe consistencies between one substrate measurement recipe of a plurality of substrate measurement recipes and each other substrate measurement recipe of the plurality of substrate measurement recipes; calculating a function of the recipe consistencies; eliminating the one substrate measurement recipe from the plurality of substrate measurement recipes if the function meets a criterion; and reiterating the determining, calculating and eliminating until a termination condition is met. Also disclosed herein is a substrate measurement apparatus, including a storage configured to store a plurality of substrate measurement recipes, and a processor configured to select one or more substrate measurement recipes from the plurality of substrate measurement recipes based on recipe consistencies among the plurality of substrate measurement recipes.