SHG Metrology With Pump-Probe Defect Differentiation
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Solution Overview
Problem
Existing SHG-based metrology tools have limited adoption due to an inability to distinguish between interfacial properties and quantify detected contaminants, such as electrically active anomalies like copper and bond voids, relying on relative measurements that are not practically able to parse between different types of anomalies.
Innovation Solution
A system utilizing a pump and probe light source combination, including a UV flash lamp as a pump and a femto-second laser as a probe, to excite electrons in layered semiconductor substrates, allowing for faster and more accurate determination of material properties by monitoring transient electric field decay and charge carrier dynamics, enabling quantitative differentiation and quantification of defects and contaminants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SHG-based metrology tools are used, then the measurement process is simple, but the ability to distinguish between interfacial properties and quantify defect types is limited
Solution Approach 1:
The patent segments the measurement process into distinct temporal phases using pump-probe methodology: the pump pulse creates charge carriers and the probe pulse measures the SHG signal at different time delays. This temporal segmentation allows differentiation of various interfacial properties and defect types that would be indistinguishable in conventional simultaneous measurement approaches.
Solution Approach 2:
The pump pulse performs preliminary action by generating charge carriers and establishing electric fields before the probe pulse arrives. This preliminary action enables the probe to detect transient phenomena and spectroscopic parameters that reveal detailed information about interfacial properties, contaminants, and bond voids.
2Measurement precision
If conventional SHG techniques are used, then the equipment is simple, but the quantification of defect types and contaminants is not precise
Solution Approach 1:
The patent employs periodic pumping at controlled repetition rates to generate transient electric fields that decay over time. By measuring the periodic SHG signal decay between pump pulses, the system extracts spectroscopic parameters such as charge carrier lifetimes and trap energies, enabling precise quantification of defect types and contaminants that would be undetectable with single-shot measurements.
3Measurement precision
If relative measurements are used, then the measurement process is straightforward, but the ability to capture quantitative information for real-time analysis is limited
Solution Approach 1:
The patent implements feedback mechanisms where the measured SHG signal decay characteristics are used to adjust and optimize subsequent measurements. The system captures transient electric field decay data and uses it to refine quantification of interfacial properties in real-time, reducing the need for extensive post-processing and enabling immediate process control decisions.
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 faster and more accurate characterization of semiconductor devices by reducing time required for measurements, allowing for real-time detection and differentiation of interfacial properties and contaminants, improving production yield and device performance.
Implementation Method 1
a UV flash lamp and a femtosecond laser to induce charge carriers
Implementation Method 2
Second-Harmonic generation is a non-linear optical effect comprising conversion of light having one frequency into light at twice that frequency upon scattering from some types of materials, structures, and geometries
Data Source
AI summary
Systems and methods are disclosed for using second-harmonic generation of light to monitor the manufacturing process for changes that can affect the performance or yield of produced devices and/or determining critical dimensions of the produced device. A sample characterization system directs light onto a sample to produce second harmonic generation (SHG) signals and a detector generates detected SHG signals in response to receiving second harmonic generation (SHG) signals from the sample. A hardware processor receives detected SHG signals and determines a geometric feature of the sample or a variation in the geometric feature of the sample based on the detected SHG signals.