Combined Ellipsometry and Optical Stress Detection System
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Solution Overview
Problem
Current systems for ellipsometry and optical stress generation and detection are typically separate, limiting their ability to measure a wide range of film thicknesses and materials, particularly opaque materials thicker than 50 angstroms, and requiring multiple systems for comprehensive characterization.
Innovation Solution
A combined system that can be configured to perform both ellipsometry and optical stress generation and detection using a controllable retarder, which modifies the polarization of light beams, allowing for the determination of various sample characteristics in a single tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate systems are used for ellipsometry and optical stress generation and detection, then each technique can be optimized for its specific application, but the device complexity increases and the ability to measure a wide range of film thicknesses and materials is limited
Solution Approach 1:
The patent combines ellipsometry and optical stress generation and detection into a single integrated system. The system uses a single optical platform that can perform both measurement techniques by switching between different optical configurations, thereby reducing the need for multiple separate systems while maintaining the measurement capabilities of both techniques
Solution Approach 2:
The integrated system is designed to perform multiple functions - both ellipsometry measurements and optical stress generation/detection measurements - using a common optical platform. This multi-functional design allows the system to measure a wide range of film thicknesses and materials without requiring separate specialized systems
2Measurement precision
If ellipsometry is used for transparent materials, then measurement precision is improved for thin films, but the technique cannot effectively measure opaque materials thicker than 50 angstroms
Solution Approach 1:
The system is designed to be universal in its ability to measure different material types. By integrating both ellipsometry and optical stress generation and detection capabilities, the system can automatically select the appropriate measurement technique based on the sample characteristics, enabling measurement of both transparent thin films and opaque materials thicker than 50 angstroms
3Measurement precision
If multiple separate systems are used for comprehensive sample characterization, then measurement precision for different material types is improved, but the ease of operation decreases and multiple locations cannot be efficiently tested on a single wafer
Solution Approach 1:
The patent merges multiple characterization capabilities into a single operational platform. The integrated system allows users to perform both ellipsometry and optical stress generation and detection measurements on the same sample using a single optical setup, eliminating the need to physically move samples between different systems and enabling efficient testing of multiple locations on a single wafer
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 the measurement of both transparent and opaque materials with varying thicknesses from above 50 angstroms down to 10 angstroms, facilitating the testing of multiple locations and characteristics on a single wafer with enhanced sensitivity and reduced noise.
Implementation Method 1
at least one first control signal is applied to a controllable retarder that modifies at least polarization of a light beam directed to a surface of a sample
Implementation Method 2
the polarization change of a light beam is measured when the light beam is reflected by the sample
Implementation Method 3
the pump beam could generate a stress wave that causes properties of a layer on the sample to change
Data Source
AI summary
A method includes selecting one of performing ellipsometry or performing optical stress generation and detection. The method also includes, in response to selecting performing ellipsometry, applying at least one first control signal to a controllable retarder that modifies at least polarization of a light beam, and performing ellipsometry using the modified light beam. The method further includes, in response to selecting performing optical stress generation and detection, applying at least one second control signal to the controllable retarder, and performing optical stress generation and detection using the modified light beam. Apparatus and computer readable media are also disclosed.