Lithography Overlay Correction with Substrate Group-Based Metrology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current lithographic processes face challenges in accurately measuring and correcting overlay and alignment residuals, which are difficult to trace back to their root causes, leading to inefficiencies in high-volume manufacturing due to the need for extensive measurement operations and time-consuming correction strategies.
Innovation Solution
A method and system that determine process corrections for lithographic processes by assigning substrates to groups based on pre-exposure parameter data and post-exposure metrology, allowing for dynamic updating of corrections to optimize run-to-run control strategies and improve throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full overlay measurement is performed on each substrate to achieve wafer level control, then manufacturing precision is improved, but productivity deteriorates due to prohibitive time and throughput loss
Solution Approach 1:
The patent segments substrates into different groups based on pre-exposure parameter data characteristics. Instead of measuring every substrate individually, only representative substrates from each group are measured, and corrections are applied to all substrates in the group. This segmentation reduces the number of measurements required while maintaining correction accuracy.
Solution Approach 2:
The patent performs preliminary classification of substrates into groups based on pre-exposure parameter data before the actual overlay measurement and correction process. This preliminary action enables the system to determine which substrates need detailed measurement and which can rely on group-based corrections, significantly reducing measurement time and improving throughput.
2Measurement precision
If extensive measurement operations are performed to accurately trace root causes of overlay residuals, then measurement precision is improved, but loss of time increases due to time-consuming correction strategies
Solution Approach 1:
The patent extracts and utilizes pre-exposure parameter data that already contains information about substrate characteristics and potential sources of overlay errors. By analyzing this extracted data beforehand, the system can identify patterns and group substrates without performing extensive measurements on all substrates, thus reducing measurement time while maintaining precision.
Solution Approach 2:
The system performs preliminary analysis of pre-exposure parameter data to identify substrate groups and their characteristics before actual overlay measurement. This preliminary action allows the system to focus measurements only on representative substrates from each group, significantly reducing the time required for accurate measurement and correction determination.
3Productivity
If group-based corrections are applied to substrates, then productivity is improved by reducing measurement time, but manufacturing precision may deteriorate compared to individual substrate corrections
Solution Approach 1:
The patent applies local quality by providing different correction approaches for different substrate groups based on their specific characteristics. Substrates with similar pre-exposure parameter profiles are grouped together and receive tailored corrections appropriate to their group characteristics, rather than applying a uniform correction approach to all substrates. This maintains precision while improving efficiency.
Solution Approach 2:
The system dynamically determines the appropriate correction approach for each substrate group based on their pre-exposure parameter data characteristics. The correction strategy adapts to the specific properties of each group, allowing the system to optimize the balance between measurement time and correction accuracy for different substrate types and processing conditions.
Data Source
AI summary
A method of determining a correction for a process parameter related to a lithographic process, wherein the lithographic process includes a plurality of runs during each one of which a pattern is applied to one or more substrates. The method of determining includes obtaining pre-exposure metrology data describing a property of a substrate; obtaining post-exposure metrology data comprising one or more measurements of the process parameter having been performed on one or more previously exposed substrates; assigning, based on the pre-exposure metrology data, a group membership status from one or more groups to the substrate; and determining the correction for the process parameter based on the group membership status and the post-exposure metrology data.