Mid-Infrared Pattern Inspection for Stacked Silicon Circuits
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Solution Overview
Problem
Detecting defects in internal circuit patterns of three-dimensional circuits is challenging with existing inspection methods.
Innovation Solution
A pattern inspection apparatus and method using light with a wavelength band of 1.2 to 5.0 micrometers to detect transmitted and reflected light from stacked silicon substrates, employing detectors and an inspection unit to analyze diffraction images for defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing inspection methods are used for three-dimensional circuits, then planar circuit inspection is possible, but internal circuit pattern defect detection is difficult
Solution Approach 1:
The patent transitions from planar (2D) inspection to three-dimensional inspection by utilizing light scattering phenomena that occur when light passes through stacked silicon substrates. The inspection system detects defects in internal circuit patterns by analyzing light scattered from different depths within the stacked structure, enabling inspection in the vertical dimension rather than only on the surface plane.
Solution Approach 2:
The patent changes the wavelength parameter of the inspection light to the mid-infrared region (1.2-5.0 micrometers), which allows the light to penetrate silicon substrates effectively. This parameter change enables the light to interact with internal circuit patterns through the stacked structure, making defect detection possible where visible or ultraviolet light would be blocked by the silicon material.
2Measurement precision
If nanometer-order light is applied to circuit patterns, then diffraction images can be obtained for defect detection, but the method is limited to planar circuits
Solution Approach 1:
The patent creates a universal inspection method that can inspect both planar circuits and three-dimensional stacked circuits using the same mid-infrared light scattering principle. The inspection system is designed to handle various circuit configurations by analyzing light scattered from different depths, making the method adaptable to multiple circuit architectures rather than being limited to a single type.
Solution Approach 2:
The patent extends the diffraction-based inspection method from two-dimensional planar surfaces into the third vertical dimension by detecting light scattered from internal layers of stacked substrates. The inspection system captures scattering signals that contain information about defects at different depths within the stacked structure, enabling three-dimensional defect detection capability.
3Reliability
If light with wavelength 1.2 to 5.0 micrometers is used, then transmitted and reflected light can be detected from stacked silicon substrates, but the system requires specialized detectors
Solution Approach 1:
The patent replaces complex mechanical inspection methods (such as physical sectioning or destructive testing) with optical detection using mid-infrared light scattering. The inspection system uses non-contact light scattering measurement to detect internal defects, eliminating the need for mechanical sample preparation or destruction while achieving reliable defect detection in three-dimensional stacked circuits.
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 non-destructive detection of internal circuit defects in three-dimensional circuits by analyzing transmitted and reflected mid-infrared light diffraction patterns.
Implementation Method 1
The detector is configured to detect transmitted light of the inspection target or reflected light of the inspection target out of the light emitted from the light source. The transmitted light is light transmitted through the inspection target. The reflected light is light reflected by the inspection target.
Implementation Method 2
employing detectors and an inspection unit to analyze diffraction images for defect detection
Data Source
AI summary
A pattern inspection apparatus includes a light source, a detector, and an inspection unit. The light source is configured to emit light toward an inspection target including stacked silicon substrates. The light has a wavelength band that is greater than or equal to 1.2 micrometers and less than or equal to 5.0 micrometers. The detector is configured to detect transmitted light of the inspection target or reflected light of the inspection target out of the light emitted from the light source. The transmitted light is light transmitted through the inspection target. The reflected light is light reflected by the inspection target. The inspection unit is configured to perform pattern inspection on the basis of a detection result obtained by the detector.