Overlay Error Noise Filtering for Semiconductor Alignment
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Solution Overview
Problem
In semiconductor fabrication, the reduction of feature sizes leads to increased complexity and accuracy challenges due to misalignment, lithography defects, and tool drift, resulting in significant overlay errors, often referred to as 'noise', which degrade the accuracy of overlay control in semiconductor manufacturing processes.
Innovation Solution
A system and method for overlay monitoring and control that includes a controller coupled with a patterning tool and a metrology tool, utilizing an overlay control module to perform statistical analysis and apply noise filtering algorithms to improve overlay correction accuracy by identifying and removing noise from overlay errors, thereby enhancing the alignment quality of semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes are reduced to increase functional density, then production efficiency is improved and costs are lowered, but overlay errors increase due to misalignment and tool drift
Solution Approach 1:
The patent implements a feedback mechanism where overlay errors are measured using metrology tools, analyzed through statistical processes, and used to adjust patterning tool parameters. This closed-loop control system continuously monitors and corrects overlay errors, enabling the system to maintain manufacturing precision while operating at reduced feature sizes for higher productivity.
Solution Approach 2:
The patent changes operational parameters of the patterning tool based on statistical analysis of overlay error data. By adjusting parameters such as alignment settings and exposure conditions according to measured deviations, the system compensates for tool drift and misalignment, maintaining overlay accuracy despite scaling to smaller feature sizes.
2Measurement precision
If statistical analysis and noise filtering are applied to overlay errors, then overlay correction accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent segments the overlay error data into different components: systematic errors that follow predictable patterns and random noise that does not. By separating these components through statistical analysis and applying different correction strategies to each, the system achieves high measurement precision while managing processing complexity through structured data organization and targeted analysis methods.
Data Source
AI summary
The present disclosure provides a system. The system includes a metrology tool configured to collect overlay errors from a patterned substrate; and a controller module coupled to the metrology tool and configured to generate an overlay compensation from the collected overlay errors, wherein the generating of the overlay compensation includes identifying a portion of the overlay errors as a set of outliers, identifying inside the set of outliers overlay errors not due to reticle effects, thereby creating a set of noise, excluding the set of noise from overlay errors, thereby creating a set of filtered overlay errors, and calculating the overlay compensation based on the set of filtered overlay errors.