Wafer Imaging Tilt Correction for Precise Substrate Testing
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Solution Overview
Problem
Existing substrate test apparatuses face challenges in obtaining accurate substrate images and reducing reliability and precision due to substrate tilting issues caused by deformation, contaminants, misalignment, and component dislocation.
Innovation Solution
A substrate test apparatus equipped with a substrate tilt measurement device to measure and correct optical path and mounting angle deviations, using a lighting device, substrate image detection device, and optical path correction device to ensure precise imaging and focusing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If substrate mounting is performed without tilt measurement and correction, then the testing process is simple and fast, but the image accuracy and test reliability are reduced due to substrate tilting
Solution Approach 1:
The apparatus is divided into independent functional modules: a substrate mounting unit, a separate tilt measurement unit with measurement light source and detection device, and an image acquisition unit. This segmentation allows the tilt correction function to be added without completely redesigning the system, improving reliability while controlling complexity through modular architecture.
Solution Approach 2:
A tilt measurement device acts as an intermediary between the substrate mounting unit and the image acquisition unit. This intermediary measures the substrate tilt state and provides correction information, enabling accurate imaging without requiring direct intervention in the mounting process itself, thus balancing reliability improvement with apparatus complexity.
2Measurement precision
If tilt measurement and optical path correction devices are added, then image precision and reliability are improved, but the apparatus complexity increases
Solution Approach 1:
The tilt measurement device uses the same optical path and detection resources as the main imaging system. The measurement light source and detection device can operate independently for tilt measurement or be integrated with the main illumination and imaging paths, allowing multi-functionality that improves measurement precision while avoiding duplicate components that would increase complexity.
Solution Approach 2:
The system changes optical parameters (light source wavelength, detection sensitivity, optical path configuration) rather than adding entirely new physical components. By adjusting measurable parameters like light intensity, wavelength, and detection angle, the system achieves high image precision through parameter optimization rather than through complex structural additions.
3Manufacturing precision
If the substrate is not tilted to a normal angle, then the mounting process is faster, but the obtained substrate image becomes inaccurate for testing
Solution Approach 1:
The tilt measurement is performed preliminarily before the main image acquisition process. By measuring the substrate tilt state in advance and calculating the required correction, the system prepares correction data that can be applied during imaging, ensuring image accuracy without requiring manual intervention or repeated adjustments that would reduce productivity.
Solution Approach 2:
The system implements a feedback mechanism where the tilt measurement device continuously monitors substrate orientation and provides real-time correction information to the optical path adjustment mechanism. This closed-loop feedback ensures that image accuracy is maintained throughout the testing process without requiring slow manual recalibration, thus preserving both precision and productivity.
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 apparatus achieves highly precise and reliable substrate imaging by correcting optical path and mounting angle deviations, enhancing test equipment reliability and precision.
Implementation Method 1
a measurement light source for generating measurement light
Implementation Method 2
at least one measurement light lens for adjusting a focus of the measurement light
Implementation Method 3
a first reflection mirror for reflecting at least a portion of the measurement light toward the substrate
Implementation Method 4
a measurement light image detection device for receiving reflected measurement light of the measurement light reflected from the substrate
Implementation Method 5
a lighting device for irradiating illumination light to a substrate
Implementation Method 6
a substrate image detection device for forming an image of the substrate by receiving light reflected from the substrate
Data Source
AI summary
Provided is a substrate test apparatus and method capable of testing or measuring a substrate such as a wafer by obtaining an optical image from the substrate, the substrate test apparatus including a lighting device for irradiating illumination light to a substrate, a substrate image detection device for forming an image of the substrate by receiving light reflected from the substrate, and a substrate tilt measurement device for measuring a tilt of the substrate based on a normal angle.