Multi-Height Level Sensor for Substrate Tilt Detection
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Solution Overview
Problem
Current level sensors in charged-particle beam inspection systems face limitations in detecting substrate displacement at multiple target heights, leading to inaccurate measurements and potential damage to inspection samples due to instability and inadequate detection of tilt, especially as feature sizes in IC manufacturing continue to shrink.
Innovation Solution
A multi-working height level sensor system that uses a configurable broadband radiation source, optical lens group, and light reflecting components to split radiation beams into multiple beamlets, each reflecting off the substrate at different target heights, enabling high-accuracy detection of height variations and tilt, and minimizing material effects on measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-target-height level sensor is used, then the device complexity is low, but the adaptability to multiple target heights is insufficient
Solution Approach 1:
The level sensor is divided into multiple independent detection channels, each with its own beam splitter and light reflecting component configured for a specific target height. This segmentation allows each channel to independently detect substrate height at its designated target height, enabling multi-target height detection while maintaining simple individual channel structures.
Solution Approach 2:
The level sensor system is designed to perform multiple detection functions simultaneously by incorporating multiple light reflecting components, each associated with different target heights. The system can detect substrate height deviations at multiple target heights in parallel, making the sensor universally applicable to various inspection scenarios without requiring separate sensors for each height.
2Measurement precision
If broadband radiation is used, then the measurement accuracy is improved by minimizing material effects, but the device complexity increases
Solution Approach 1:
The system employs broadband radiation covering multiple wavelengths instead of single-wavelength light sources. This parameter change in the radiation source enables the system to minimize material-induced measurement errors by selecting optimal wavelengths for different substrate materials, thereby improving height detection accuracy across diverse IC components.
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 solution allows for precise detection of substrate deviations at various target heights, improving imaging quality, reducing material-induced errors, and ensuring the substrate is parallel to the reference surface, thus preventing damage and enhancing the stability of the inspection system.
Implementation Method 1
a beam splitter configured to split the radiation beam into multiple beamlets that each reflect off the substrate
Implementation Method 2
a beam splitter configured to split the radiation beam into multiple beamlets
Implementation Method 3
multiple light reflecting components, wherein each light reflecting component is associated with one of the beamlets reflecting off the substrate and is configured to support a different target height for the substrate by detecting a height or a levelness of the substrate based on the beamlet reflecting off the substrate
Data Source
AI summary
An inspection apparatus for adjusting a working height for a substrate for multiple target heights is disclosed. The inspection apparatus includes a radiation source configured to provide a radiation beam and a beam splitter configured to split the radiation beam into multiple beamlets that each reflect off a substrate. Each beamlet contains light of multiple wavelengths. The inspection apparatus includes multiple light reflecting components, wherein each light reflecting component is associated with one of the beamlets reflecting off the substrate and is configured to support a different target height for the substrate by detecting a height or a levelness of the substrate based on the beamlet reflecting off the substrate.