Lithographic Apparatus Control via Substrate-Specific Metrology Corrections
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Solution Overview
Problem
Current methods for controlling lithographic apparatuses in semiconductor manufacturing do not effectively account for substrate-to-substrate variations, leading to inconsistent pattern reproduction and overlay errors.
Innovation Solution
A method is developed to determine control settings for a lithographic apparatus by combining first corrections based on historical metrology data with second corrections derived from residual errors specific to each substrate, using alignment and overlay data to optimize patterning for each substrate individually.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If per lot correction methods are used for overlay control, then manufacturing process control is simplified, but substrate-to-substrate variations cannot be accounted for leading to inconsistent pattern reproduction
Solution Approach 1:
The patent segments the correction approach by introducing substrate-specific metrology measurements and individual correction values for each substrate, rather than applying a single per-lot correction. This segmentation enables accounting for substrate-to-substrate variations while maintaining systematic control through automated measurement and correction application.
Solution Approach 2:
The patent changes the correction parameter from a general per-lot overlay correction to substrate-specific corrections based on individual metrology measurements. By measuring and correcting each substrate individually, the system adapts to substrate variations, improving pattern reproduction consistency while maintaining process control through automated parameter adjustment.
2Manufacturing precision
If substrate-specific corrections are implemented, then pattern reproduction consistency improves, but measurement and control complexity increases
Solution Approach 1:
The patent implements self-service by having the lithographic apparatus automatically perform metrology measurements on each substrate and apply substrate-specific corrections without requiring external intervention. The system measures its own performance characteristics and self-corrects, reducing the need for complex external measurement infrastructure while improving pattern reproduction consistency.
Solution Approach 2:
The patent establishes a feedback loop where metrology measurements of each substrate feed into automated correction calculations, which then adjust the lithographic process parameters for that substrate. This closed-loop feedback system automatically compensates for substrate variations, improving pattern reproduction while managing complexity through systematic automated control.
3Measurement precision
If comprehensive metrology measurement infrastructure is deployed to measure each substrate, then overlay control accuracy improves, but processing time and productivity decrease
Solution Approach 1:
The patent merges the metrology measurement function with the lithographic exposure process by integrating measurements directly into the lithographic apparatus workflow. By combining measurement and exposure operations in a single integrated system, the patent achieves accurate overlay measurement without requiring separate measurement equipment, thereby maintaining productivity while improving measurement precision.
Data Source
AI summary
A method of determining a control setting for a lithographic apparatus. The method includes obtaining a first correction for a current layer on a current substrate based on first metrology data associated with one or more previous substrates, and obtaining a second correction for the current layer on the current substrate. The second correction is based on a residual determined based on second metrology data associated with a previous layer on the current substrate. The method further includes determining the control setting for the lithographic apparatus for patterning the current layer on the current substrate by combining the first correction and the second correction.