Thermoreflectance Microscopy for Sub-Micron Semiconductor Defect Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current defect analysis methods for semiconductor devices face limitations in spatial resolution and accuracy, particularly with the fine patterning and high integration of modern semiconductor devices, leading to difficulties in tracking defect positions and measuring heat distribution effectively across various materials.
Innovation Solution
A defect analysis apparatus and method utilizing heat distribution measurement with a spatial resolution of 1 μm or less, employing a phase-lock thermal reflection method, synchronized light detection, and spectral imaging to determine optimal wavelengths for high-resolution and sensitive thermal imaging, allowing non-contact tracking and analysis of defect positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If infrared thermal emission technique is used to detect hot spots from semiconductor defects, then defect detection capability is improved, but spatial resolution is limited to about 3 μm due to optical diffraction limit
Solution Approach 1:
The patent replaces the infrared thermal emission technique with thermoreflectance microscopy. Instead of detecting infrared radiation emitted by hot spots, the system uses visible or ultraviolet light to illuminate the sample and measures reflectivity changes caused by temperature variations. This substitution of the detection mechanism enables sub-micron spatial resolution while maintaining defect detection capability.
Solution Approach 2:
The patent changes the measurement parameter from infrared thermal emission to reflectivity change in the visible or ultraviolet range. By measuring how reflectivity varies with temperature rather than detecting emitted infrared radiation, the system achieves higher spatial resolution limited only by the illumination wavelength and optical system, not by the diffraction limit of infrared detection.
2Measurement precision
If focused ion beam (FIB) is used to cut the semiconductor wafer for defect analysis, then defect cause analysis accuracy is improved, but the sample is damaged and analysis time increases
Solution Approach 1:
The patent replaces the mechanical cutting process (FIB) with a non-contact optical measurement technique. By using thermoreflectance microscopy to directly image and analyze defects in their original positions, the system eliminates the time-consuming FIB cutting and SEM observation process while maintaining the ability to determine defect causes through heat distribution patterns.
Solution Approach 2:
The patent creates an optical copy or image of the defect location and characteristics through thermoreflectance microscopy. Instead of physically cutting and examining the sample, the system captures thermal images that replicate the defect information, allowing analysis without sample destruction or time-consuming preparation.
3Productivity
If conventional defect inspection equipment is used, then productivity is maintained, but spatial resolution cannot meet the requirements of fine patterned semiconductor devices
Solution Approach 1:
The patent replaces conventional infrared-based defect inspection equipment with thermoreflectance microscopy using visible or ultraviolet light sources. This substitution enables sub-micron spatial resolution suitable for fine patterned devices while maintaining productivity through non-contact, non-destructive measurement that does not require sample preparation or destruction.
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 high-accuracy defect position tracking and heat distribution measurement with improved spatial resolution, overcoming the limitations of commercialized defect inspection tools and effectively analyzing defects in semiconductor devices with various materials.
Implementation Method 1
a first detection unit configured to detect light reflected from a surface of the sample
Implementation Method 2
a power supply unit configured to generate a driving signal in order to periodically heat the sample for localized heat at a defect point of the sample
Implementation Method 3
the distribution of reflectivity change due to the hot spot of the sample is measured by a phase-lock thermal reflection method, and then the heat distribution of the sample is derived from the measured result
Data Source
AI summary
The present invention provides a method for analyzing defects by using heat distribution measurement, comprising: a sample loading unit for loading a sample to check whether or not there is a defect through heat distribution characteristics; a light source for radiating visible light onto the sample; a power supply unit for generating a driving signal in order to periodically heat the sample; a detection unit for detecting reflected light from the surface of the sample; and a signal generator for synchronizing the detection unit with the driving signal of the power supply unit.