Semiconductor Overlay Key Measurement Using Multi-ROI Light Detection
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Solution Overview
Problem
The increasing complexity of semiconductor manufacturing processes, particularly with finer line widths and new materials, has made overlay measurement in semiconductor devices more challenging, leading to inaccuracies due to damaged overlay keys and step differences.
Innovation Solution
The method involves dividing the overlay key into multiple regions of interest (ROI) and using distinct measurement lights to detect overlay errors, optimizing the overlay recipe for improved accuracy by irradiating specific areas of the overlay keys with tailored measurement lights.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the overlay key is used for overlay measurement in highly integrated semiconductor devices, then overlay measurement can be performed, but the overlay key is damaged due to step differences and new materials, making measurement inaccurate
Solution Approach 1:
The overlay key is divided into multiple regions of interest (ROIs), each corresponding to different pattern areas. This segmentation allows selective measurement in undamaged regions while excluding damaged areas, thereby maintaining measurement accuracy despite partial overlay key damage caused by step differences and new materials.
Solution Approach 2:
Different measurement conditions and parameters are applied to different ROIs based on their local characteristics. By tailoring the measurement approach to each specific region's condition, the system optimizes measurement accuracy for each area while compensating for local damage or variations in the overlay key structure.
2Manufacturing precision
If complex processes and materials are applied to achieve finer line widths, then manufacturing capability is improved, but the difficulty of measuring and evaluating these processes increases
Solution Approach 1:
The measurement process is segmented into multiple ROIs with different measurement conditions. This breaks down the complex overall measurement task into manageable regional measurements, reducing the difficulty of detecting and evaluating complex processes while maintaining the capability to measure finer line widths.
Solution Approach 2:
The measurement system dynamically adjusts measurement parameters and ROI selection based on the specific characteristics of each region and the complexity of the local process. This dynamic adaptation simplifies the measurement of complex processes by tailoring the approach to each specific measurement context.
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 approach enhances the accuracy of overlay measurement by focusing on specific areas of the overlay keys, reducing the impact of damage and step differences, thereby improving the reliability of the measurement process.
Implementation Method 1
irradiating a first measurement light to a first region of interest (ROI) over first portions of the first and second patterns to detect a first overlay error
Data Source
AI summary
A method of manufacturing a semiconductor device includes forming a first lower overlay key including first and second patterns in a lower layer, forming a first upper overlay key including third and fourth patterns in an upper layer vertically disposed on the lower layer, irradiating a first measurement light to a first region of interest (ROI) over first portions of the first and second patterns to detect a first overlay error and irradiating a second measurement light to a second ROI over second portions of the first and second patterns, the second ROI being different from the first ROI, to detect a second overlay error.