Multiple Mode Imager for Substrate Inspection
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Solution Overview
Problem
Current inspection systems for substrates like semiconductor wafers and printed circuit boards can only perform a single optical mode scan at a time, limiting the types of information gathered during the manufacturing process.
Innovation Solution
A multiple mode imager system that alternates between different optical modes during a single scan, using a movable optical element with varying portions to switch between optical paths, allowing for the capture of images with different optical characteristics such as polarization, wavelength, and illumination angles, and combining these images to provide comprehensive data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If a single optical mode scan is used, then the inspection system is simple and easy to operate, but the amount of information gathered is limited
Solution Approach 1:
The patent combines multiple optical modes (dark field, bright field, polarized light, phase contrast) into a single inspection system that can capture images in different optical modes during one scan, thereby gathering comprehensive information without requiring multiple separate scans or systems
Solution Approach 2:
The inspection system is designed to perform multiple functions by switching between different optical modes during a single scan, allowing one system to replace what would traditionally require multiple specialized inspection systems
2Loss of information
If multiple optical mode scans are performed separately, then comprehensive information is gathered, but the inspection time increases
Solution Approach 1:
The system performs continuous scanning while alternating between different optical modes, ensuring that the scan process is not interrupted and that information gathering continues uninterrupted across multiple optical perspectives
Solution Approach 2:
The illumination sources are activated in periodic alternation during the scan, with different optical modes being cycled through systematically to capture comprehensive data within a single continuous scan period
3Productivity
If multiple cameras are used for different optical modes, then multiple data sets are captured simultaneously, but the device complexity increases
Solution Approach 1:
The patent employs movable optical elements (such as rotating mirrors or beam switches) that dynamically redirect light from the objective lens to different cameras based on the current optical mode, allowing flexible allocation of imaging paths without requiring fixed dedicated paths for each mode
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
Enables the acquisition of multiple data sets per point on the substrate during a single scan, enhancing the inspection capabilities by providing combined images that represent various optical modes, thereby improving the efficiency and effectiveness of substrate inspection.
Implementation Method 1
Each radiation reflecting element, when entering the collection path directs radiation from the substrate towards a first camera of the multiple mode imager
Data Source
AI summary
A multiple mode evaluation system that includes a multiple mode imager that is arranged to perform a single scan of a substrate while alternating between different optical modes thereby producing different sets of images of areas of the substrate, each set of images being associated with a single optical mode of image acquisition; wherein the different optical modes differ from each other by at least one optical characteristic.