Lithography Metrology Split Patterns for Best Focus and Dose
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Solution Overview
Problem
Current lithography technologies face challenges in accurately determining the best focus and dose for forming critical dimensions of photoresist patterns, which are crucial for semiconductor device manufacturing, as existing methods rely heavily on operator experience and lack precise, data-driven approaches.
Innovation Solution
A lithography metrology method that involves acquiring focus and dose sensitivity data, selecting patterns with high sensitivity to these parameters, and forming split patterns on a substrate to determine the best focus and dose through controlled exposure and development processes, allowing for precise measurement and optimization of critical dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If operator experience is used to determine best focus and dose, then the process is simple and quick, but the precision and reliability of determination are insufficient
Solution Approach 1:
The substrate is divided into multiple chip regions, with each region containing specific test patterns (focus patterns and dose patterns) designed to measure sensitivity to focus and dose variations. This segmentation allows systematic collection of sensitivity data across different regions, enabling precise determination of best focus and dose through data analysis rather than operator experience
Solution Approach 2:
The method involves varying focus and dose parameters across different chip regions to create measurable differences in pattern formation. By systematically changing these parameters and measuring the resulting critical dimensions, the method establishes quantitative relationships between parameters and pattern quality, enabling objective determination of optimal settings
2Manufacturing precision
If traditional lithography monitoring methods are used, then the process flow is simple, but the ability to accurately monitor and optimize critical dimensions is limited
Solution Approach 1:
Test patterns are pre-designed and formed on the substrate before production lithography. These patterns are specifically configured to be highly sensitive to focus and dose variations, allowing preliminary characterization of the lithography process conditions. This preliminary action enables optimization of actual production parameters based on measured sensitivity data
Solution Approach 2:
The method establishes a feedback loop where critical dimensions of test patterns are measured, sensitivity data is analyzed, and this information is used to adjust and optimize lithography parameters. The measured CD values from focus and dose patterns provide feedback on process performance, enabling continuous improvement of manufacturing precision
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 method enables accurate determination of the best focus and dose for lithography processes, improving the precision and reliability of semiconductor manufacturing by relying on digitized focus and dose sensitivity data rather than operator experience, and effectively forming patterns with desired critical dimensions.
Implementation Method 1
exposing and developing the photoresist
Data Source
AI summary
A lithography metrology method is provided. Focus sensitivity data and dose sensitivity data of sample patterns to be formed on a substrate are acquired. At least one focus pattern selected in descending order of focus sensitivity from among the acquired focus sensitivity data of the sample patterns is determined. At least one low-sensitivity focus pattern in ascending order of the focus sensitivity from among the acquired dose sensitivity data of the sample patterns is selected, and at least one dose pattern selected in descending order of dose sensitivity from among the at least one low-sensitivity focus pattern is determined. A split substrate having a plurality of chip regions is prepared. A plurality of focus split patterns having a shape corresponding to the at least one focus pattern and a plurality of dose split patterns having a shape corresponding to the at least one dose pattern in the plurality of chip regions are formed. A best focus and a best dose from the plurality of focus split patterns and the plurality of dose split patterns are determined.