Acoustic Wave Inspection for Multilayer Pattern Defects
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Solution Overview
Problem
Existing inspection methods for multilayer pattern structures, especially those with optically opaque materials like metals, struggle to detect defects in lower layers non-destructively, requiring destructive testing and prolonged time and cost for verification.
Innovation Solution
A pattern structure inspection apparatus utilizing a chaotic wave sensor that generates and analyzes 3D speckle images through multiple-scattered laser beams, allowing for non-destructive detection of defects in both top and underlying patterns by amplifying scattered waves and comparing them to reference patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical observation methods are used to inspect pattern structures, then top layer defects can be detected, but defects in lower layers are concealed and cannot be detected
Solution Approach 1:
The patent transitions from conventional optical observation (2D surface inspection) to acoustic wave-based inspection (3D volumetric inspection). By using acoustic waves that can penetrate through opaque materials and interact with defects at different depths, the system achieves three-dimensional defect detection capability, allowing simultaneous detection of both top and lower layer defects without being limited to surface-level observation.
Solution Approach 2:
The patent replaces the optical inspection system with an acoustic inspection system. Instead of using light that cannot penetrate opaque materials, the system uses acoustic waves (ultrasonic waves) that can propagate through and interact with the pattern structure, enabling detection of defects in lower layers that are concealed from optical observation.
2Measurement precision
If destructive testing methods are used to detect lower layer defects, then detection accuracy improves, but inspection time and cost increase significantly
Solution Approach 1:
The patent employs a non-destructive acoustic inspection method that allows defects to be detected while the product remains intact and functional. The acoustic waves interact with the material's internal structure and defects, providing inspection capability without requiring destructive sampling, cutting, or disassembly, thus eliminating the time loss associated with destructive testing and subsequent reconstruction.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to probe the pattern structure. These acoustic waves can penetrate the material, interact with defects, and carry information back to the sensor without causing damage to the inspected object, enabling non-destructive detection that maintains product integrity while providing accurate defect information.
3Measurement precision
If multiple inspection methods are used to detect both top and lower layer defects, then detection completeness improves, but device complexity increases
Solution Approach 1:
The patent describes a unified acoustic inspection system that can detect defects at multiple depths and in different layers using a single inspection method. The acoustic wave-based system provides universal detection capability for both top and lower layer defects, eliminating the need for multiple separate inspection systems (optical for top layer, destructive methods for lower layers) and reducing overall system complexity.
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
Enables rapid, non-destructive detection of defects in multilayer pattern structures, reducing inspection time and costs while improving detection accuracy for both top and underlying layers.
Implementation Method 1
a wave from a wave source is multiple-scattered in a sample
Implementation Method 2
grain-shaped speckles are generated due to constructive or destructive interference between the waves
Data Source
Figure 1A~1B
Figure 2
Figure 3~4A
AI summary
According to an aspect of the present invention, there is provided a pattern structure inspection method including irradiating a wave from a wave source onto a sample including a pattern region in which a structure having a certain pattern is provided on a substrate, collecting speckle data generated due to multiple scattering of the wave in the pattern region, by using a data collector, and analyzing whether the structure of the pattern region has a defect, by comparing the collected speckle data to reference speckle data.