Variable Angle Spectroscopic Scatterometer for Profile Sensitivity
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Solution Overview
Problem
Current spectroscopic reflectometry and ellipsometry systems face challenges in sensitivity to profile variables and measurement correlation between critical dimensions, particularly due to fixed angles of incidence and difficulties in calibrating and stabilizing these systems for precise measurements at advanced technology nodes.
Innovation Solution
The system optimizes sensitivity by determining a set of desired measurement angles, including both azimuth and polar angles, using a spectroscopic measurement model to direct an incident beam towards a sample, thereby reducing measurement correlation and enhancing data accuracy through precise angle adjustments and high power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed angle of incidence is used in SE systems, then the system is simple to operate and calibrate, but the sensitivity to profile variables is reduced and measurement correlation occurs
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed angle of incidence to a variable angle of incidence that can be adjusted based on the specific measurement requirements. The system dynamically changes the AOI to optimize sensitivity for different profile variables while maintaining operational simplicity through automated control.
Solution Approach 2:
The patent changes the parameter of angle of incidence from a fixed value to a variable parameter that can be optimized for different measurement conditions. This allows the system to adapt to different sample types and measurement goals, improving sensitivity without requiring complex manual adjustment.
2Measurement precision
If varying angles of incidence are used to optimize sensitivity, then measurement precision improves, but system complexity and calibration difficulty increase
Solution Approach 1:
The system performs self-calibration and self-stabilization by automatically determining the optimal angle of incidence based on the measurement model and sample characteristics. This eliminates the need for manual calibration procedures and maintains measurement accuracy without requiring complex external calibration equipment or procedures.
Solution Approach 2:
The patent implements feedback mechanisms where the system continuously monitors measurement quality and adjusts the angle of incidence accordingly. This feedback loop ensures that the system maintains optimal sensitivity and accuracy while automatically compensating for any drift or instability, reducing the need for manual intervention.
3Adaptability or versatility
If two synchronized rotating elements are used to change beam angles, then the system can measure multiple parameters, but the difficulty of calibration and maintaining stability increases
Solution Approach 1:
The patent extracts the angle adjustment function from complex synchronized rotating mechanisms and implements it through a simpler variable angle of incidence approach. This isolation of the critical function allows the system to maintain versatility while significantly reducing calibration complexity and stability maintenance requirements.
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 allows for highly accurate measurements by optimizing sensitivity to profile variables, reducing measurement correlation, and maintaining high precision and stability, especially in semiconductor production lines, where advanced technology nodes require precise calibration and high accuracy.
Implementation Method 1
spectroscopic reflectometry and ellipsometry systems
Implementation Method 2
a diffraction beam is diffracted from the sample in response to the incident beam
Data Source
AI summary
Techniques for optimizing the sensitivity of spectroscopic measurement techniques with respect to certain profile variables by selecting desired measurement angles since the measurement sensitivity to each variable depends, at least in part, on the measurement angles of an incident beam. The selected desired set of measurement angles includes both an azimuth angle and a polar angle. Optimizing the sensitivity of spectroscopic measurement techniques can also reduce or eliminates measurement correlation among variable to be measured.