Electrode-less Plasma Broadband Illuminator for Semiconductor Inspection
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Solution Overview
Problem
Conventional broadband light illuminators for semiconductor defect inspection suffer from low optical intensity and non-uniformity across various incident angles due to the presence of electrodes, which absorb and alter the light path, reducing the efficiency and accuracy of defect detection.
Innovation Solution
A broadband light illuminator with an electrode-less chamber generating plasma broadband light, utilizing an elliptical reflector and lens unit to focus the light onto the inspection object, ensuring uniform incidence across a wide range of angles without light loss, and using laser emitters to provide energy for ionizing gases and forming a plasma state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If electrodes are used in the broadband light illuminator, then the light can be generated, but the optical intensity and uniformity across various incident angles deteriorate due to light absorption and path alteration by electrodes
Solution Approach 1:
The patent removes electrodes from the light generation chamber entirely, extracting the harmful element that causes non-uniform light distribution. The electrodes are replaced with an electrode-less plasma discharge mechanism that generates broadband light without introducing absorbing structures into the light path, thereby achieving both high optical intensity and uniformity across all incident angles.
2Measurement precision
If conventional broadband light illuminators are used, then defect inspection can be performed, but the detection accuracy and efficiency deteriorate due to low optical intensity
Solution Approach 1:
The patent replaces the conventional electrode-based electrical discharge system with a laser-based energy input system. Laser emitters provide controlled energy to generate plasma without requiring physical electrodes, resulting in higher optical intensity broadband light that improves defect detection accuracy while maintaining the plasma light generation mechanism.
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 solution achieves higher optical intensity and uniformity of the inspection light across all incident angles, enhancing the detection of minute defects with improved accuracy and efficiency, regardless of the inspection mode.
Implementation Method 1
a first energy provider, at an exterior of the chamber, configured to provide first energy for ionizing high pressure gases in the chamber to form high pressure ionized gases in the chamber
Implementation Method 2
a second energy provider, at the exterior of the chamber, configured to provide second energy for transforming the ionized gases into a plasma state to form the plasma area at a central portion of the chamber
Implementation Method 3
an electrode-less chamber including a plasma area from which broadband light is generated
Implementation Method 4
an elliptical reflector having a first focus at which the chamber is positioned and a second focus such that the broadband light is reflected from the elliptical reflector toward the second focus
Implementation Method 5
a lens unit focusing the reflected broadband light onto the inspection object to form an inspection light for detecting the defects of the inspection object
Data Source
AI summary
A broadband light illuminator of an optical inspector for optically detecting defects of an inspection object may include an electrode-less chamber including a plasma area from which broadband light is generated; a first energy provider, exterior to the chamber, configured to provide first energy for ionizing high pressure gases to form ionized gases in the chamber; a second energy provider, exterior to the chamber, configured to provide second energy for transforming the ionized gases into a plasma state to form the plasma area at a central portion of the chamber; an elliptical reflector having a first focus at which the chamber is positioned and a second focus such that the broadband light is reflected from the elliptical reflector toward the second focus; and a lens unit focusing the reflected broadband light onto the inspection object to form an inspection light for detecting the defects of the inspection object.