Alignment Mark Signal Weighting for Local Distortion Correction
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Solution Overview
Problem
Existing alignment determination methods in semiconductor manufacturing fail to account for local dimensional distortions in alignment marks, leading to reduced accuracy in alignment determination.
Innovation Solution
Detect local dimensional distortions of alignment marks by irradiating them with radiation and measuring phase and/or amplitude shifts in reflected radiation, weighting the alignment signal based on symmetrical areas to reduce the influence of distorted regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing alignment determination methods are used, then the process is simple, but alignment accuracy deteriorates due to local dimensional distortions in alignment marks
Solution Approach 1:
The alignment mark is divided into multiple local regions, and the alignment signal is segmented into multiple local alignment signals corresponding to different regions. This allows identification of local dimensional distortions in specific regions without compromising the overall alignment measurement capability.
Solution Approach 2:
Different weighting factors are applied to different local alignment signals based on the quality of each region. Regions with dimensional distortions receive lower weighting, while regions with high symmetry and no distortions receive higher weighting, optimizing the overall alignment signal quality.
2Reliability
If alignment marks with local dimensional distortions are used, then manufacturing is easier, but alignment measurement reliability deteriorates
Solution Approach 1:
The method changes the parameters used to evaluate alignment marks by introducing symmetry assessment and local region analysis. Instead of relying on traditional global alignment measurements, the system evaluates multiple parameters including local symmetry, dimensional consistency, and signal quality to identify reliable regions for alignment determination.
Solution Approach 2:
The system provides feedback by identifying which local regions of the alignment mark are suitable for measurement and which are distorted. This feedback mechanism allows the alignment determination process to adaptively select and weight signals from reliable regions, improving overall measurement reliability.
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
Enhances alignment determination accuracy by minimizing the impact of local distortions, improving the precision of alignment in semiconductor device manufacturing processes.
Implementation Method 1
detecting one or more phase and/or amplitude shifts in reflected radiation from the geometric feature
Implementation Method 2
detecting one or more phase and/or amplitude shifts in reflected radiation from the geometric feature, the one or more phase and/or amplitude shifts corresponding to one or more local dimensional distortions of the geometric feature
Data Source
AI summary
A method for generating an alignment signal that includes detecting local dimensional distortions of an alignment mark and generating the alignment signal based on the alignment mark. The alignment signal is weighted based on the local dimensional distortions of the alignment mark. Detecting the local dimensional distortions can include irradiating the alignment mark with radiation, the alignment mark including a geometric feature, and detecting one or more phase and/or amplitude shifts in reflected radiation from the geometric feature. The one or more phase and/or amplitude shifts correspond to the local dimensional distortions of the geometric feature. A parameter of the radiation, an alignment inspection location within the geometric feature, an alignment inspection location on a layer of a structure, and/or a radiation beam trajectory across the geometric feature may be determined based on the one or more detected phase and/or amplitude shifts.