Quasi-Offner HSI Apparatus with Planar Grating
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Solution Overview
Problem
Current hyperspectral imaging (HSI) apparatuses face challenges in achieving reliable spectral resolution and mass productivity, particularly in semiconductor inspection, due to the complexity of curved gratings and limited numerical aperture, which affects the accuracy and efficiency of defect detection and material analysis.
Innovation Solution
The proposed HSI apparatus incorporates a quasi-Offner configuration with a planar reflective grating and an aspherical mirror, along with a slit plate and cameras, to generate hyperspectral images, enhancing spectral and spatial resolution and improving reliability through improved optical path compensation and mass-productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If curved gratings are used in HSI apparatus, then spectral resolution can be improved, but device complexity and manufacturing difficulty increase significantly
Solution Approach 1:
The patent applies spheroidality by using an aspherical mirror instead of traditional spherical or flat mirrors in the HSI apparatus. The aspherical mirror has a curved surface with specific aspherical coefficients that enable it to focus light more effectively and improve spectral resolution while maintaining manufacturing feasibility through precise surface figuring.
Solution Approach 2:
The patent employs parameter changes by optimizing the aspherical mirror surface equation parameters (aspherical coefficients C40, C60, C80) and the grating groove density (1200 lines/mm) to achieve the desired spectral resolution. By carefully selecting and adjusting these parameters, the system attains high spectral resolution without requiring complex curved gratings.
2Productivity
If numerical aperture is increased to improve inspection efficiency, then productivity increases, but optical aberrations and measurement precision deteriorate
Solution Approach 1:
The aspherical mirror's curved surface is specifically designed to handle high numerical aperture beams (NA=0.08) while correcting optical aberrations. The aspherical shape enables the system to maintain both high productivity through increased NA and high spectral resolution by properly focusing the divergent beams across the wide angular range.
Solution Approach 2:
The patent implements a dynamic scanning mechanism that moves the sample stage in the vertical direction to capture hyperspectral data. This dynamic approach allows the system to maintain high inspection efficiency by continuously acquiring data from different depths and positions,充分利用 the high numerical aperture for rapid data collection.
3Reliability
If conventional HSI apparatus configuration is used, then device simplicity is maintained, but reliability and spectral resolution are insufficient for semiconductor inspection
Solution Approach 1:
The aspherical mirror provides superior optical performance with reduced aberrations compared to conventional spherical mirrors, significantly improving the reliability of spectral measurements. The precise aspherical surface figure ensures consistent focusing across the field of view, making the system reliable for semiconductor defect detection.
Solution Approach 2:
The patent replaces the traditional curved grating mechanical component with a planar grating combined with an aspherical mirror optical system. This substitution maintains the spectral resolution performance while simplifying the mechanical structure and improving mass productivity, thereby enhancing overall system reliability.
4Ease of manufacture
If planar reflective grating with aspherical mirror is used, then mass productivity and ease of manufacture improve, but achieving high spectral resolution becomes more challenging
Solution Approach 1:
The patent achieves high spectral resolution with a planar grating by carefully optimizing the aspherical mirror parameters (surface equation coefficients) and the grating groove density (1200 lines/mm). This parameter optimization allows the use of simpler planar gratings that can be manufactured with high precision using standard fabrication techniques, enabling mass production while maintaining spectral resolution.
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 configuration enhances the spectral resolution and spatial resolution, allowing for more precise spectrum data and improved reliability in defect detection and material analysis, while being more suitable for industrial applications like semiconductor fabrication.
Implementation Method 1
a first aspherical mirror configured to reflect the introduced output beam
Implementation Method 2
a first grating having a planar reflective surface, the first grating configured to generate a plurality of first split beams by splitting the output beam after being reflected by the first aspherical mirror
Implementation Method 3
a first camera configured to detect the plurality of first split beams
Implementation Method 4
a dichroic mirror configured to split an output beam into a first output beam having a first wavelength band and a second output beam having a second wavelength band
Data Source
AI summary
Provided is a hyperspectral imaging (HSI) apparatus. The HSI apparatus includes: a first slit plate configured to introduce an output beam; a first aspherical mirror configured to reflect the introduced output beam; a first grating having a planar reflective surface, the first grating configured to generate a plurality of first split beams by splitting the output beam after being reflected by the first aspherical mirror; and a first camera configured to detect the plurality of first split beams.