Pupil Plane Light Modulation for Precise Semiconductor Pattern Measurement
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in measuring small patterns due to resolution issues and decreased measurement accuracy, with limitations in optical resolution methods such as short wavelength and high numerical aperture techniques.
Innovation Solution
A pupil image measuring device and method that includes a light source, optical system, detector, and spatial light distribution controller, with the controller adjusting light intensity or amount on a conjugate pupil plane to improve measurement precision and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a short wavelength method is used to improve optical resolution, then measurement precision is improved, but light quantity becomes insufficient
Solution Approach 1:
The patent changes the wavelength parameter of light to a shorter range (e.g., ultraviolet or extreme ultraviolet) to improve optical resolution for measuring smaller patterns. This parameter change enables higher precision measurement but results in reduced light quantity, which is compensated by other means in the system.
2Measurement precision
If a high numerical aperture method is used to improve optical resolution, then measurement precision is improved, but the size of the objective lens reaches a physical limit
Solution Approach 1:
The patent increases the numerical aperture parameter of the objective lens to improve optical resolution. However, this parameter cannot be increased indefinitely due to physical constraints on lens size and manufacturing capabilities, creating a limitation in further improving measurement precision through this method alone.
3Measurement precision
If multiple measurements are performed to improve measurement accuracy, then measurement precision is improved, but measurement time increases
Solution Approach 1:
The patent applies spatial light distribution control to create non-uniform light intensity distribution across the measurement field, with higher intensity in regions requiring more precise measurement. This local quality adjustment allows for improved measurement accuracy in critical areas without requiring multiple measurements across the entire field, thereby reducing total measurement time.
4Device complexity
If uniform light distribution is used to simplify the optical system, then device complexity is reduced, but measurement precision decreases due to reflectivity deviation
Solution Approach 1:
The patent implements spatial light distribution control to create a non-uniform light intensity distribution that compensates for the angular dependence of reflectivity. Different regions of the pupil plane receive different light intensities, allowing for more accurate reflectivity measurements across varying incidence angles without significantly increasing overall system complexity.
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 device enables rapid and precise measurement of semiconductor devices by reducing reflectivity deviations and improving signal-to-noise ratio, requiring fewer measurements to achieve uniform brightness and enhancing measurement speed.
Implementation Method 1
the optical system includes an objective lens configured to condense the light
Implementation Method 2
a spatial light distribution controller configured to adjust an intensity or amount of a light output from the light source or the reflected light, for each space of a plurality of spaces of the spatial light distribution controller
Implementation Method 3
a detector configured to detect a light reflected from the measurement target
Data Source
AI summary
Provided is a pupil image measuring device including a light source configured to generate and output a light, a stage on which a measurement target is loaded, an optical system configured to transmit the light output from the light source, to the measurement target, a detector configured to detect a light reflected from the measurement target, and a spatial light distribution controller configured to adjust an intensity or amount of the light output from the light source or the reflected light, for each space of a plurality of spaces of the spatial light distribution controller, wherein the spatial light distribution controller is disposed on a pupil plane.