Exposure Light Beam Property Estimation from Wavefront Fringe Patterns
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Solution Overview
Problem
Existing photolithography systems face challenges in accurately determining the spectral properties of exposure light beams, particularly the convolved bandwidth, which affects the critical dimension of semiconductor features, due to complex and error-prone computational methods.
Innovation Solution
An estimation system that utilizes a non-linear relationship between sensed wavefronts of an initial light beam to determine properties of an exposure light beam, specifically using fringe patterns and calibration parameters to estimate convolved bandwidth, providing a straightforward and accurate approach.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex computational methods are used to determine spectral properties, then measurement precision may be improved, but device complexity and error-proneness increase
Solution Approach 1:
The patent extracts only the necessary information from the fringe pattern (fringe width and intensity) and uses it directly in a simplified computational formula to determine spectral properties, eliminating the need for complex multi-step computations while maintaining accuracy
Solution Approach 2:
The patent creates a simplified mathematical model that copies the essential characteristics of the complex spectral distribution into an equivalent form that can be computed directly from fringe pattern measurements, avoiding the need to work with the full complex spectrum
2Measurement precision
If direct spectral measurement methods are used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses the fringe pattern as an intermediary that translates complex spectral information into a simpler form that can be measured and computed more easily, serving as a bridge between the complex spectrum and the measurement system
Solution Approach 2:
The patent replaces direct spectral analysis mechanisms with fringe pattern analysis, substituting a simpler measurement approach that uses wavefront interference patterns instead of direct spectral decomposition
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 offers a robust and efficient method to estimate convolved bandwidth, correlating well with critical dimension, ensuring consistent and high-quality semiconductor feature production across different optical systems.
Implementation Method 1
an optical measurement system configured to produce a fringe pattern based on the light beam
Data Source
AI summary
An apparatus includes: an estimation system configured to: determine a set of values related to an initial light beam based on sensed wavefronts of the initial light beam, the set of values including a first value and a second value. The estimation system is also configured to determine an estimate of a property of an exposure light beam based on a non-linear relationship that includes the first value and the second value. The exposure light beam is formed by interacting the initial light beam with an optical system. The apparatus also includes a communications module coupled to the estimation system and configured to output the estimate of the property of the exposure light beam.