Phased Array Coherence Scrambling for High-Speed Feature Metrology
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Solution Overview
Problem
Metrology systems face challenges in accurately and efficiently measuring densely packed lithographic features on substrates, particularly in high-volume manufacturing environments, requiring improved measurement speed and accuracy to maintain production yields.
Innovation Solution
A metrology system incorporating a phased array with optical elements, waveguides, and phase modulators generates a beam of radiation with controlled incoherence through phase randomization, enabling rapid and precise measurement of substrate features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional coherent illumination sources are used in metrology systems, then measurement precision can be maintained, but measurement speed is insufficient for high-volume manufacturing rates
Solution Approach 1:
The patent changes the coherence parameter of the illumination source from coherent to incoherent while maintaining measurement precision through advanced signal processing algorithms and optimized detection methods, thereby enabling faster measurement speeds suitable for high-volume manufacturing
Solution Approach 2:
The patent replaces traditional mechanical scanning measurement systems with a static illumination field approach using incoherent sources, eliminating moving parts and enabling parallel measurement of multiple features simultaneously, thus dramatically increasing measurement speed
2Productivity
If measurement speed is increased to match high-volume manufacturing rates, then productivity improves, but measurement precision deteriorates
Solution Approach 1:
The patent introduces advanced signal processing algorithms and computational methods as intermediaries between the incoherent illumination source and the final measurement result, extracting precise feature dimensions from the scattered incoherent light patterns through mathematical reconstruction techniques
Solution Approach 2:
The patent uses computational modeling and simulation to create virtual copies of the measurement process, comparing actual measurements against extensive libraries of simulated patterns to determine feature dimensions with high precision even from incoherent illumination data
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 enhances measurement speed and accuracy of densely packed features by utilizing a phased array to generate incoherent radiation beams, improving the capability of metrology tools to keep pace with high-volume manufacturing rates.
Implementation Method 1
waveguides configured to guide radiation from the radiation source to the optical elements
Implementation Method 2
phase modulators configured to adjust phases of the radiation waves such that the radiation waves accumulate to form the beam, wherein an amount of incoherence of the beam is based on randomization of the phases
Data Source
AI summary
A system includes a radiation source and a phased array. The phased array includes optical elements, waveguides and phase modulators. The phased array generates a beam of radiation. The optical elements radiate radiation waves. The waveguides guide radiation from the radiation source to the optical elements. The phase modulators adjust phases of the radiation waves such that the radiation waves accumulate to form the beam. An amount of incoherence of the beam is based on randomization of the phases.