Automated Metrology Target Design for Lithography Process Control
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Solution Overview
Problem
Current metrology target designers face challenges in generating accurate and process-compatible designs for complex lithography processes, such as spacer-based double lithography and FinFET processes, due to labor-intensive manual measurements and limitations in handling process-induced complexities and geometrical alterations.
Innovation Solution
The Design for Control (D4C) methodology automates the generation of robust metrology targets by modeling individual steps of a lithography process into a single sequence, allowing for real-time visualization and selection of optimal targets that are compatible with various lithography processes and perturbations, using a computer-implemented method that designs three-dimensional geometrical structures based on process parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual measurement and design methods are used for metrology targets, then designers can handle simple lithography processes, but the process becomes labor-intensive and time-consuming for complex processes
Solution Approach 1:
The system enables self-service by allowing the metrology target design to be automatically generated through computer-aided design based on process parameters. The CAD system automatically creates target structures without requiring manual measurement and drawing, thereby improving productivity while reducing time loss.
2Manufacturing precision
If manual design methods are used, then flexibility in handling various processes is maintained, but design accuracy decreases for complex lithography processes
Solution Approach 1:
The patent introduces a computer-aided design system as an intermediary between the lithography process parameters and the metrology target design. This CAD system automatically translates process parameters into accurate target structures, ensuring manufacturing precision while managing the complexity of lithography processes through automated computation rather than manual design.
3Measurement precision
If frequent manual measurement is performed for process control, then accurate process verification is achieved, but the process becomes labor-intensive
Solution Approach 1:
The system applies preliminary action by pre-generating multiple metrology target designs with varying structures through computer-aided design. These pre-designed targets are then automatically selected based on process requirements, eliminating the need for frequent manual measurement and design while maintaining measurement precision and improving ease of operation.
4Productivity
If automated CAD design is implemented, then productivity and accuracy are improved, but the system becomes more complex
Solution Approach 1:
The patent replaces the mechanical manual design system with an automated computer-aided design system. This substitution uses computational algorithms to automatically generate metrology target designs based on process parameters, significantly improving productivity and accuracy. The system complexity is managed through software automation rather than manual procedures.
Data Source
AI summary
Methods and systems for automatically generating robust metrology targets which can accommodate a variety of lithography processes and process perturbations. Individual steps of an overall lithography process are modeled into a single process sequence to simulate the physical substrate processing. That process sequence drives the creation of a three-dimensional device geometry as a whole, rather than “building” the device geometry element-by-element.