Combined Ellipsometry and Scatterometry for Phase-Aware Metrology
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Solution Overview
Problem
Existing metrology systems for semiconductor manufacturing lose valuable phase and scattering information, limiting the ability to accurately measure critical dimensions and structural asymmetries of semiconductor wafers.
Innovation Solution
A combined ellipsometry and scatterometry system that utilizes a radiation source generating wavelengths from 0.1 to 100 nm, rotating polarization elements, and detectors to capture both spectral reflection and scattering radiation, enabling simultaneous measurement of phase and scattering information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If scatterometry or reflectometry is used for metrology applications, then measurement capability is provided, but phase information is lost
Solution Approach 1:
The patent combines scatterometry and reflectometry into a single measurement system that simultaneously captures both scattered intensity and phase information. The system uses a detector array to record scattered radiation patterns while also measuring phase shifts through interferometric techniques, merging two previously separate measurement approaches into one integrated solution that recovers both intensity and phase data.
Solution Approach 2:
The patent introduces an interferometric measurement path as an intermediary between the sample and detector. This intermediary path allows phase information to be encoded into the scattered radiation by creating interference patterns, enabling the phase data to be recovered through standard intensity detection without requiring direct phase measurement capabilities.
2Measurement precision
If ellipsometry is used for visible-infrared wavelengths, then phase measurement is enabled, but scattering information is lost
Solution Approach 1:
The patent merges ellipsometry's phase measurement capability with scatterometry's scattering detection by using a detector array that can simultaneously resolve both the angular distribution of scattered radiation and the phase shifts. The system combines the polarimetric measurement approach of ellipsometry with the angular scattering detection of scatterometry into a unified measurement framework.
Solution Approach 2:
The patent adds the phase dimension to the traditional scatterometry measurement space. Instead of only measuring scattered intensity as a function of angle, the system measures both intensity and phase, creating a four-dimensional measurement space (angle, wavelength, polarization, phase) that captures complete scattering information including structural asymmetry data.
3Ease of operation
If only reflective intensity or scattered intensity is used for measurements, then measurement simplicity is maintained, but valuable structural information is lost
Solution Approach 1:
The patent replaces the need for complex mechanical phase measurement devices with an optical interferometric approach. Instead of using mechanical modulators or complex phase-shifting hardware, the system uses optical interference to encode phase information into intensity patterns that can be captured by standard detectors, maintaining operational simplicity while recovering structural information.
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
The system provides enhanced sensitivity for measuring critical dimensions and structural asymmetries, such as tilt, overlay, and aperiodicity, without additional computational cost, improving yield management in semiconductor manufacturing.
Implementation Method 1
A radiation source is provided that generates radiation having at least one wavelength from 0.1 to 100 nm
Implementation Method 2
One or more rotating elements are provided that change polarization of the radiation and/or relative phase between two polarizations of the radiation
Implementation Method 3
At least one detector is provided that receives spectral reflection and scattering radiation from the workpiece
Implementation Method 4
At least one detector is provided that receives spectral reflection and scattering radiation from the workpiece
Data Source
AI summary
A system includes a radiation source that generates radiation having at least one wavelength from 0.1 to 100 nm. One or more rotating elements change polarization of the radiation and/or relative phase between two polarizations of the radiation. A stage is configured to hold a workpiece in a path of the radiation. At least one detector receives spectral reflection and scattering radiation from the workpiece.