Semiconductor Measurement With Angular Polarization Interference
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Solution Overview
Problem
Existing semiconductor measurement apparatuses face challenges in accurately determining critical dimensions due to interactions between different dimensions, leading to inaccuracies in spectral distribution measurements.
Innovation Solution
A semiconductor measurement apparatus that obtains data across a wide range of incidence angles and azimuths, using polarization components' interference patterns to determine critical dimensions through a Mueller matrix, employing compensators and beam displacers to separate and interfere light components accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ellipsometry is used to measure critical dimension at fixed azimuth and incidence angle, then measurement process is simple, but measurement accuracy deteriorates due to interaction between different critical dimensions
Solution Approach 1:
The patent extends the measurement from a single fixed azimuth and incidence angle to multiple azimuth angles (0-360 degrees) and wide range of incidence angles. By acquiring spectral distribution data across multiple dimensional parameters (azimuth and incidence angle variations), the system resolves the interaction between different critical dimensions through comprehensive angular sampling, thereby improving measurement accuracy without significantly complicating the measurement process
Solution Approach 2:
The patent changes the measurement parameters by varying the azimuth angle across 0-360 degrees and using a wide range of incidence angles instead of fixed values. This parameter variation allows the system to capture how different critical dimensions affect spectral distribution under different angular conditions, enabling accurate determination of the target critical dimension despite interactions with other dimensions
2Productivity
If spectral distribution is obtained from ellipsometry at fixed angles, then measurement is fast, but determination of critical dimension becomes inaccurate
Solution Approach 1:
The patent performs preliminary action by pre-acquiring comprehensive spectral distribution data across all azimuth angles (0-360 degrees) and wide incidence angle ranges in a single measurement setup. This preliminary comprehensive data acquisition eliminates the need for multiple separate measurements at different angles, maintaining measurement speed while providing sufficient data to accurately determine critical dimensions despite interactions between different dimensions
3Measurement precision
If multiple measurements are performed at different angles to improve accuracy, then measurement precision improves, but measurement time increases
Solution Approach 1:
The patent merges multiple measurement angles (all azimuth angles from 0-360 degrees and wide incidence angle ranges) into a single integrated measurement process. By combining all angular measurements into one comprehensive spectral distribution acquisition, the system achieves accurate critical dimension determination without requiring sequential measurements at different angles, thereby eliminating time loss while maintaining high 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
Enables precise measurement of selected critical dimensions by reducing the influence of interacting dimensions, improving measurement stability and semiconductor process yield.
Implementation Method 1
using polarization components' interference patterns to determine critical dimensions
Implementation Method 2
obtain, by processing the original image, a selected critical dimension among critical dimensions of a structure included in a region of the sample to which light is incident
Data Source
AI summary
A semiconductor measurement apparatus may include an illumination unit configured to irradiate light to the sample, an image sensor configured to receive light reflected from the sample and output multiple interference images representing interference patterns of polarization components of light, an optical unit in a path through which the image sensor receives light and including an objective lens above the sample, and a control unit configured to obtain, by processing the multi-interference image, measurement parameters determined from the polarization components at each of a plurality of azimuth angles defined on a plane perpendicular to a path of light incident to the image sensor. The control unit may be configured to determine a selected critical dimension to be measured from a structure in the sample based on measurement parameters. The illumination unit and/or the optical unit may include a polarizer and a compensator having a ¼ wave plate.