Wafer Inspection via Spectral Cube Generation
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Solution Overview
Problem
Current methods for inspecting semiconductor wafers are time-consuming and inefficient, requiring sequential irradiation of light on multiple points to obtain spectra, which prolongs the inspection process and can lead to measurement errors.
Innovation Solution
A method involving broadband light irradiation to generate a spectral cube, which includes multiple spectral images representing reflectivity or phase variations across pixels, allowing for simultaneous inspection of a wafer region with reduced time and error through spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential irradiation of light on multiple points is used to obtain spectra, then measurement precision can be maintained, but inspection time increases significantly
Solution Approach 1:
The patent transitions from sequential point-by-point measurement to simultaneous spectral imaging across the entire wafer surface. By using a spectral imaging system that captures multiple wavelengths at multiple spatial positions simultaneously, the inspection process moves from a 1D sequential scan to a 2D/3D parallel measurement, dramatically reducing inspection time while maintaining measurement precision through comprehensive spectral data collection.
Solution Approach 2:
The patent combines multiple spectral measurements at different spatial positions into a single simultaneous imaging operation. The spectral imaging camera captures reflectivity spectra across the entire wafer surface in one operation, merging what would otherwise require many separate sequential measurements into a single parallel process, thus reducing total inspection time while preserving measurement accuracy.
2Measurement precision
If sequential inspection method is used, then measurement precision is maintained, but productivity decreases
Solution Approach 1:
The patent applies spectral imaging to capture the entire wafer surface and its spectral characteristics in a single operation, transforming the inspection from a sequential 1D process to a parallel 2D/3D process. This dimensional change enables simultaneous measurement of multiple regions, significantly increasing throughput while maintaining the precision of spectral analysis through comprehensive data capture.
Solution Approach 2:
The spectral imaging system continuously captures spectral data across the entire wafer surface without interruption or sequential pauses. The useful action of measuring reflectivity and phase variations occurs simultaneously across all inspection regions, eliminating the downtime and sequential constraints of traditional methods, thereby maximizing productivity while preserving measurement accuracy.
3Productivity
If broadband light irradiation is used to generate spectral cube, then inspection speed increases significantly, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical scanning systems with a spectral imaging camera that performs parallel optical measurement. Instead of mechanically moving a sensor point-by-point across the wafer surface, the system uses an optical sensor array that simultaneously captures spectral data across the entire surface, substituting mechanical complexity with optical parallel processing to achieve high inspection speed.
Solution Approach 2:
The spectral imaging camera serves multiple functions simultaneously: it captures spatial information, spectral reflectivity data, and phase variations all in one operation. This multi-functional device consolidates what would otherwise require multiple separate measurement systems into a single universal instrument, achieving high productivity while managing device complexity through functional integration.
4Loss of time
If spectral cube generation from single light irradiation is used, then inspection time is reduced, but measurement precision may be compromised
Solution Approach 1:
The patent uses spectral imaging to capture three-dimensional spectral data (spatial coordinates + wavelength) simultaneously across the wafer surface. By measuring reflectivity and phase variations at multiple wavelengths and positions in a single operation, the system achieves both rapid inspection and high measurement precision through comprehensive spectral characterization without requiring sequential measurements.
Solution Approach 2:
The spectral imaging system continuously and simultaneously captures complete spectral data across the entire wafer surface without interruption. This continuous parallel measurement ensures that all spectral information is captured in one operation, maintaining measurement precision by avoiding the potential errors and data loss that can occur during sequential measurement transitions, while dramatically reducing inspection time.
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 approach significantly reduces inspection time by tens or hundreds of times, increases inspection efficiency, and eliminates the need for pattern recognition hardware, providing accurate and rapid analysis of wafer patterns and material layers.
Implementation Method 1
irradiating broadband light on the wafer, such that the light is reflected from the wafer
Data Source
AI summary
A method of inspecting a wafer includes performing a fabricating process on a wafer, irradiating broadband light on the wafer, such that the light is reflected from the wafer, generating a spectral cube by using the light reflected from the wafer, extracting a spectrum of a desired wafer inspection region from the spectral cube, and inspecting the desired wafer inspection region by analyzing the extracted spectrum.