Speckle-Based Semiconductor Measurement for Wide-View CD Inspection
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Solution Overview
Problem
Semiconductor measurement apparatuses face limitations in both angle of view and resolution, making it difficult to improve inspection efficiency and accuracy when capturing images of pattern shapes in a non-destructive manner.
Innovation Solution
A semiconductor measurement apparatus that uses a light source to output coherent light, a pattern generator to create a speckle pattern, and an image sensor to generate original images, with a controller adjusting optical models to optimize the prediction and result images, thereby enhancing the angle of view and resolution by comparing prediction images with original images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a measurement apparatus captures images of pattern shapes in a non-destructive manner, then the structure and shape of patterns can be inspected, but the angle of view and resolution are limited
Solution Approach 1:
The invention segments the measurement process into two distinct modes: a first measurement mode that captures a wide-angle image of the entire pattern shape, and a second measurement mode that captures high-resolution images of specific critical dimension regions. This segmentation allows the system to obtain both broad inspection coverage and detailed measurement precision by dividing the measurement task into complementary parts.
Solution Approach 2:
The invention dynamically switches between two measurement modes based on the inspection needs. The control unit determines whether to perform a comprehensive shape inspection (first measurement mode) or detailed critical dimension measurement (second measurement mode) by analyzing the captured images and making real-time decisions about which measurement approach to apply, thereby optimizing both angle of view and resolution as needed.
2Area of stationary object
If the angle of view is increased to capture more of the pattern, then the inspection coverage is improved, but the resolution decreases
Solution Approach 1:
The invention segments the measurement process into two distinct modes: a first measurement mode that captures a wide-angle image of the entire pattern shape, and a second measurement mode that captures high-resolution images of specific critical dimension regions. This segmentation allows the system to obtain both broad inspection coverage and detailed measurement precision by dividing the measurement task into complementary parts.
Solution Approach 2:
The invention adds a temporal dimension to the measurement process by performing measurements at different times and with different parameters. The system first captures a wide-angle overview image, then based on analysis of that image, selectively captures high-resolution images of specific regions, thereby resolving the resolution-coverage tradeoff through multi-stage, time-separated measurements.
3Measurement precision
If the resolution is increased to measure critical dimensions accurately, then the measurement precision is improved, but the angle of view decreases
Solution Approach 1:
The invention segments the measurement process into two distinct modes: a first measurement mode that captures a wide-angle image of the entire pattern shape, and a second measurement mode that captures high-resolution images of specific critical dimension regions. This segmentation allows the system to obtain both broad inspection coverage and detailed measurement precision by dividing the measurement task into complementary parts.
Solution Approach 2:
The invention performs a preliminary wide-angle measurement first to identify which regions require detailed critical dimension analysis. By conducting this preliminary inspection, the system can then selectively apply high-resolution measurement only to the necessary regions, avoiding the need to perform high-resolution measurement across the entire area and thereby maintaining both coverage and precision.
4Device complexity
If a single measurement mode is used, then the device complexity is reduced, but it is difficult to improve both efficiency and accuracy
Solution Approach 1:
The invention makes the measurement apparatus universal by enabling it to perform multiple measurement functions: both wide-angle shape inspection and high-resolution critical dimension measurement. The same apparatus can adaptively switch between different measurement modes based on the inspection requirements, thereby achieving multi-functionality without requiring separate dedicated devices for each measurement type.
Solution Approach 2:
The invention dynamically switches between two measurement modes based on the inspection needs. The control unit determines whether to perform a comprehensive shape inspection (first measurement mode) or detailed critical dimension measurement (second measurement mode) by analyzing the captured images and making real-time decisions about which measurement approach to apply, thereby optimizing both angle of view and resolution as needed.
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 increases the efficiency and accuracy of inspections by improving the angle of view and resolution, allowing for more precise measurement of pattern shapes and critical dimensions.
Implementation Method 1
a light source configured to output coherent light
Implementation Method 2
a pattern generator configured to emit light including a plurality of planar waves moving in different directions to a sample by scattering the coherent light
Implementation Method 3
an image sensor configured to receive light reflected from the sample and generate an original image representing a diffractive pattern of light reflected from the sample
Data Source
AI summary
An example semiconductor measurement apparatus includes a light source, a pattern generator, a stage, an image sensor, and a controller. The light source is configured to output light in a predetermined wavelength band. The pattern generator is configured to generate light including a speckle pattern by scattering the light output from the light source. The stage is disposed on a movement path of the light including the speckle pattern, and a sample reflecting the light including the speckle pattern is seated on the stage. The image sensor is configured to receive light reflected from the sample and generate an original image representing a diffractive pattern of light reflected from the sample. The controller is configured to generate a prediction image for estimating diffractive characteristics of light incident on the image sensor.