Wafer Inspection Using Multi-Wavelength Spectral Defect Detection
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Solution Overview
Problem
Conventional wafer inspection techniques face limitations in accurately detecting structural abnormalities, particularly in the lower structures of wafers due to sampling constraints and inability to inspect non-repetitive patterns effectively.
Innovation Solution
A wafer inspection apparatus and method utilizing light with different wavelengths to obtain statistical information, inspecting patterns at multiple positions, and determining defects by analyzing spectral information not within a calculated statistical distribution region, thereby improving the reliability of semiconductor chip inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If point measurement using OCD (Optical Critical Dimension) measurement equipment is used, then accurate inspection through analysis of the 3D structure is possible, but it is difficult to inspect a front side of a wafer due to sampling limitations
Solution Approach 1:
The inspection system segments the wafer inspection into multiple wavelength bands, with each wavelength inspecting specific depth regions. Short wavelengths inspect upper structures while long wavelengths inspect lower structures, dividing the inspection task to achieve both comprehensive coverage and high precision without requiring excessive sampling points.
2Productivity
If large-area upper defect inspection using BF (Bright Field) checker is used, then front side measurement is possible through speed-up, but there is a drawback that a lower structure cannot be detected
Solution Approach 1:
The system adds the wavelength dimension to the inspection process. By using multiple wavelengths with different penetration depths, the system can simultaneously inspect both upper and lower structures across the entire wafer area, achieving high-speed comprehensive inspection without sacrificing detection capability for lower structures.
3Device complexity
If conventional inspection techniques are used, then inspection process is simple, but reliability of inspection of wafers with non-repetitive patterns is insufficient
Solution Approach 1:
The system changes the wavelength parameter of inspection light to create statistical distribution regions for different depth structures. By comparing spectral information against these wavelength-based statistical regions, the system achieves high reliability in detecting defects in non-repetitive patterns while maintaining a manageable inspection process through automated statistical analysis.
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 the reliability of wafer inspection by accurately identifying defects in semiconductor chips with non-repetitive patterns, addressing the limitations of existing methods by combining spectral information from multiple wavelengths to determine defective chips.
Implementation Method 1
providing a first light having a plurality of wavelengths to a spectrometer, splitting the first light into a second light having any one wavelength among the plurality of wavelengths using the spectrometer
Implementation Method 2
obtaining a first plurality of pieces of spectral information at the first positions using the light, obtaining a first spectral distribution information using the first plurality of pieces of spectral information
Data Source
AI summary
A method for fabricating a semiconductor device is provided. The method for fabricating the semiconductor device includes a first step of loading a first wafer including a plurality of semiconductor chips having the same pattern on a stage of a wafer inspection apparatus, a second step of inspecting the plurality of semiconductor chips using light having different wavelengths from each other, and a third step of unloading the first wafer from the stage of the wafer inspection apparatus, wherein inspecting of the plurality of semiconductor chips using the light includes inspecting patterns at the same first positions of the respective semiconductor chips, inspecting patterns at the same second positions of the respective semiconductor chips, inspecting patterns at the same k-th positions of the respective semiconductor chips, and determining the semiconductor chip having a pattern defect by combining pattern inspection results at each of the first to k-th positions.