Semiconductor Measurement Apparatus Single-Image Spectral Analysis
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Solution Overview
Problem
Existing semiconductor measurement apparatuses require repeated measurements for each wavelength to obtain spectral distributions, making the process inefficient for determining critical dimensions at all azimuthal angles and over a wide range of incidence angles.
Innovation Solution
A semiconductor measurement apparatus that includes an illumination unit providing linearly polarized light beams of different wavelengths, an optical unit with an objective lens and a beam splitter, a self-interference generator, an image sensor, and a controller. The apparatus captures a single image to obtain data for critical dimension determination at all azimuthal angles and over a wide range of incidence angles by processing the measurement image to extract intensity and phase difference information for each wavelength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If repeated measurements are performed for each wavelength to obtain spectral distribution, then measurement precision is improved, but productivity deteriorates due to time-consuming sequential measurements
Solution Approach 1:
The patent combines multiple monochromatic light sources of different wavelengths into a single illumination system. The image sensor simultaneously captures interference patterns for all wavelengths in one exposure, merging what would otherwise require sequential measurements into a single operation, thereby maintaining spectral precision while dramatically improving measurement throughput
Solution Approach 2:
The patent introduces a spectral dimension by using multiple wavelengths simultaneously. Instead of measuring one wavelength at a time in the temporal domain, the system captures all wavelengths in the spatial domain through a single image, transforming the measurement from a sequential temporal process to a parallel spatial process
2Productivity
If a single image capture is used to obtain data for all azimuthal angles and wide incidence angles, then productivity is improved, but device complexity increases due to additional optical components
Solution Approach 1:
The objective lens is designed to simultaneously perform multiple functions: it illuminates the sample at various incidence angles and collects reflection light from all azimuthal angles. This multi-functional optical element enables comprehensive angular measurement without requiring separate optical paths or components for each angle, thus improving productivity while limiting complexity growth
Solution Approach 2:
The beam splitter acts as an intermediary that separates the illumination path from the detection path. It directs monochromatic light onto the sample while simultaneously directing the reflected light from all angles to the image sensor, enabling the complex angular measurement function without requiring the illumination and detection systems to be physically integrated
3Measurement precision
If self-interference generation is implemented to extract phase information, then measurement precision is improved, but device complexity increases due to additional optical components
Solution Approach 1:
The system uses self-interference where the reflection light interferes with itself to generate the interference pattern. The beam splitter and optical path are configured so that the light naturally creates interference fringes without requiring external reference beams or complex interferometric arrangements, thereby achieving high phase measurement precision with minimal additional 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
Enables efficient measurement of critical dimensions by capturing data for all azimuthal angles and a wide range of incidence angles in a single image capture, improving the efficiency of the semiconductor measurement process.
Implementation Method 1
an illumination unit configured to provide linearly polarized light beams having different wavelengths as illumination light
Implementation Method 2
an optical unit including an objective lens configured to allow the illumination light to be incident on a sample
Implementation Method 3
a beam splitter configured to transmit reflection light generated when the illumination light is reflected from the sample
Implementation Method 4
a self-interference generator configured to self-interfere and transmit the reflection light transmitted from the beam splitter, for each wavelength
Implementation Method 5
an image sensor configured to output a measurement image including an interference pattern of the reflection light
Data Source
AI summary
A semiconductor measurement apparatus includes an illumination unit configured to provide illumination light including linearly polarized light beams having different wavelengths, an optical unit including an objective lens configured to allow the illumination light to be incident on a sample, the optical unit being configured to transmit reflection light generated when the illumination light is reflected from the sample, a self-interference generator configured to self-interfere the reflection light transmitted from the optical unit and transmit the reflection light to a first image sensor, for each wavelength, and a controller. The controller is configured to process a measurement image output by the image sensor to divide the measurement image into a first image representing an intensity ratio of a polarization component of the reflection light and a second image representing a phase difference of the polarization component of the reflection light, for each wavelength.