Wavefront Changing Unit for Multi-Wavelength Aberration Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In lithography processes, insufficient aberration correction in detection optical systems leads to measurement errors when detecting light components of multiple wavelengths, degrading the accuracy of overlay and alignment measurements on semiconductor substrates.
Innovation Solution
A measurement apparatus with a wavefront changing unit that corrects wavefront aberrations for light of different wavelengths by generating specific correction wavefronts in distinct regions, improving the detection system's accuracy by reducing aberration-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a detection optical system detects light components of multiple wavelengths simultaneously, then measurement speed is improved, but measurement precision deteriorates due to insufficient aberration correction
Solution Approach 1:
The patent divides the wavefront correction into separate regions for different wavelengths. The wavefront changing unit includes a first region for correcting wavefront aberration of first wavelength light and a second region for correcting wavefront aberration of second wavelength light. This segmentation allows each wavelength to receive appropriate correction without interference, enabling simultaneous multi-wavelength detection while maintaining high measurement precision.
Solution Approach 2:
The patent applies different wavefront correction characteristics to different regions of the optical system. Each region is optimized for specific wavelength correction, allowing the system to maintain optimal performance for multiple wavelengths simultaneously. This local optimization resolves the contradiction by ensuring that each wavelength component receives tailored correction rather than a one-size-fits-all approach.
2Measurement precision
If wavefront aberration correction is applied separately for different wavelengths, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple wavefront correction functions into a single wavefront changing unit that operates across different regions. Rather than using separate correction systems for each wavelength, the invention integrates them into one unified structure that handles multiple wavelengths simultaneously through spatial separation of correction regions, reducing overall device complexity while maintaining precision.
Solution Approach 2:
The wavefront changing unit is designed as a multi-functional component that performs wavefront correction for multiple wavelengths within a single device. This universal design allows the system to correct aberrations for different wavelengths without requiring separate dedicated correction systems, thereby reducing device complexity while achieving high measurement precision.
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 enhances the measurement accuracy of overlay and alignment errors on semiconductor substrates by effectively correcting wavefront aberrations, allowing for precise positioning and pattern formation even with multiple wavelength detection.
Implementation Method 1
a wavefront changing unit configured to change a wavefront aberration in light from the target
Implementation Method 2
the wavefront changing unit includes a first region where the light of the first wavelength enters, and a second region where the light of the second wavelength enters, and the control unit controls the wavefront changing unit such that a first correction wavefront for correcting a first wavefront aberration in the light of the first wavelength is generated in the first region, and a second correction wavefront for correcting a second wavefront aberration in the light of the second wavelength is generated in the second region
Data Source
AI summary
A measurement apparatus including an illumination system configured to illuminate a target with light including light of a first wavelength and light of a second wavelength, a wavefront changing unit configured to change a wavefront aberration in light from the target, and a control unit configured to control the wavefront changing unit, wherein the wavefront changing unit includes a first region where the light of the first wavelength enters, and a second region where the light of the second wavelength enters, and the control unit controls the wavefront changing unit such that a first correction wavefront for correcting a first wavefront aberration in the light of the first wavelength is generated in the first region, and a second correction wavefront for correcting a second wavefront aberration in the light of the second wavelength is generated in the second region.