Semiconductor Measurement Apparatus Using Polarization Interference
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Solution Overview
Problem
Semiconductor measurement apparatuses face challenges in accurately determining critical dimensions due to the increasing influence of other critical dimensions on spectral distributions, particularly as structures are miniaturized, leading to errors in measurement and difficulty in distinguishing between height and width changes in spectral distributions.
Innovation Solution
A semiconductor measurement apparatus that includes a lighting unit capable of generating output light with multiple selected wavelength bands arranged in one direction, a self-interference generator, and a controller to process interference patterns, allowing for the simultaneous acquisition of optical information and determination of critical dimensions by analyzing interference patterns of polarization components across various wavelength bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ellipsometry is used to measure critical dimensions, then measurement capability is provided, but measurement precision deteriorates as structures are miniaturized due to increased influence of other critical dimensions on spectral distribution
Solution Approach 1:
The patent segments the spectral distribution into multiple wavelength bands and separates the measurement of different critical dimensions. By dividing the spectrum into distinct bands and measuring polarization components at different wavelengths, the system can isolate the spectral signatures of individual critical dimensions, reducing the harmful influence of other dimensions on the measurement accuracy.
Solution Approach 2:
The patent introduces polarization components as an intermediary parameter to distinguish between different critical dimensions. By measuring the polarization state of light at multiple wavelengths and using the interference patterns of polarization components, the system creates an additional measurement dimension that allows separation of the effects of different critical dimensions, thereby improving measurement precision despite the presence of multiple interacting dimensions.
2Measurement precision
If multiple wavelength bands are used to measure critical dimensions, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines multiple wavelength bands and polarization component measurements into a single integrated optical path. By merging the measurement of different wavelength bands and polarization states through a unified optical system that captures interference patterns simultaneously, the patent reduces the need for separate measurement apparatuses for each wavelength and polarization component, thereby reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The patent designs an optical system that serves multiple functions simultaneously: it measures multiple critical dimensions, captures interference patterns of polarization components across different wavelength bands, and processes this information to determine critical dimension values. This multi-functional approach consolidates what would otherwise require separate measurement systems into a single apparatus, reducing device complexity while enhancing measurement capability.
3Loss of information
If comprehensive spectral distribution data is collected, then information about critical dimensions is improved, but measurement time increases
Solution Approach 1:
The patent performs preliminary processing of the spectral distribution data by identifying and selecting specific wavelength bands that are most sensitive to the critical dimensions being measured. By pre-determining which wavelength bands provide the most informative interference patterns for polarization component analysis, the system can focus measurement and processing resources on the most critical data, reducing overall measurement time while maintaining complete information about the critical dimensions.
Solution Approach 2:
The patent extracts and isolates the interference pattern information from the comprehensive spectral distribution data. By taking out only the essential interference pattern components related to polarization components at selected wavelength bands, and separating this information from the rest of the spectral data, the system reduces the amount of data that requires processing while preserving the complete information needed to determine critical dimensions, thereby reducing measurement time.
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 enables accurate and efficient measurement of critical dimensions by obtaining intensity and phase differences of polarization components in a single shot, reducing measurement time and improving accuracy despite interactions between critical dimensions.
Implementation Method 1
an optical member configured to decompose the light output by the light source into the plurality of wavelength bands
Implementation Method 2
a self-interference generator disposed on a path of a reflected light from the sample. The self-interference generator may include a Nomarski prism and at least one polarizer sequentially disposed in the path of the reflected light
Implementation Method 3
an objective lens configured to allow light having passed through the first optical unit to be incident onto a sample
Data Source
AI summary
Provided is a semiconductor measurement apparatus that includes: a lighting unit comprising a light source, and a light modulator configured to decompose a light output by the light source into a plurality of wavelength bands and generate an output light of at least two selected wavelength bands; a first optical unit comprising an illumination polarizing element disposed in a path of the output light; a second optical unit comprising a beam splitter, an objective lens configured to allow light having passed through the first optical unit to be incident onto a sample, and a self-interference generator disposed on a path of a reflected light; a sensor configured to output an original image representing an interference pattern of light having passed through the self-interference generator; and a controller configured to process the original image and determine a selected critical dimension of a structure included in the sample.