Metrology Waveguide for Target Asymmetry Measurement
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Solution Overview
Problem
Current metrology systems face challenges in accurately measuring target mark asymmetry during lithographic processes, which affects the precision and efficiency of substrate alignment and pattern formation.
Innovation Solution
A metrology system is developed that includes a projection system, a detector array, and a waveguide device. The detector array is configured to individually measure the intensity of each diffraction order and determine their distribution on the detector. A processor calculates a correction factor based on the intensity differences and distribution changes, which is then used to revise the target characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional scatterometry measures total scattered light intensity, then measurement speed is improved, but measurement precision of target asymmetry deteriorates
Solution Approach 1:
The patent divides the scattered light measurement into separate diffraction order components using a detector array with multiple detection elements. Each detection element measures the intensity of specific diffraction orders (e.g., +1, -1, +2, -2 orders) separately, enabling precise asymmetry measurement while maintaining measurement speed through parallel detection of multiple diffraction components.
2Device complexity
If a single detector measures total scattered light, then device complexity is reduced, but measurement precision of asymmetry deteriorates
Solution Approach 1:
The detection system is segmented into multiple detection elements arranged in an array, where each element is responsible for detecting specific diffraction orders. This segmentation enables precise asymmetry measurement through differential intensity comparison while keeping the overall device architecture relatively simple and scalable.
Solution Approach 2:
The patent transitions from a single-point detection approach to a spatially distributed detector array arrangement. The detection elements are positioned at different locations corresponding to different diffraction angles, adding a spatial dimension to the measurement system that enables simultaneous measurement of multiple diffraction orders and improves asymmetry detection capability.
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 solution enhances the accuracy of target mark asymmetry measurements, improves substrate alignment, and increases the efficiency of lithographic processes by providing real-time correction factors.
Implementation Method 1
receive a plurality of diffraction orders diffracted from a target on a substrate
Data Source
AI summary
Some embodiments of this disclosure can improve measurement of target mark asymmetry in metrology apparatuses for improving accuracy in measurements performed in conjunction with lithographic processes. For example, a metrology system can include a projection system configured to receive a plurality of diffraction orders diffracted from a target on a substrate. The metrology system can further include a detector array and a waveguide device configured to transmit the plurality of diffraction orders between the projection system and the detector array. The detector array can be configured to detect each of the plurality of diffraction orders spatially separate from other ones of the plurality of diffraction orders.