Telecentric Illumination Paths for Wafer Inspection
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Solution Overview
Problem
Current wafer inspection technologies face challenges in achieving high-quality detection of wafer surfaces with efficient illumination and detection systems, particularly in ensuring that a high percentage of light reaches the surface and maintaining simplicity for service accessibility without compromising inspection quality.
Innovation Solution
The apparatus incorporates telecentric illumination and detection paths for both bright field and dark field illuminations, utilizing multiple light sources and imaging optical elements, along with optical fibers and casings, to optimize light delivery and detection, ensuring homogeneous illumination and high-resolution imaging, and includes a movable assembly unit for easy service access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple illumination paths and detection paths are integrated into a single assembly unit, then the inspection quality and light utilization are improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple illumination paths (bright field, dark field) and detection paths into a single assembly unit that is movable relative to the wafer. This integration allows simultaneous multi-mode inspection capabilities while reducing the number of separate fixed systems, thereby improving inspection quality without proportionally increasing overall device complexity.
Solution Approach 2:
The assembly unit is designed to be movable (translatable and/or rotatable) relative to the wafer surface. This dynamic configuration allows the same assembly to serve multiple inspection positions and angles, enabling complex inspection functionality with a relatively simple, reconfigurable structure rather than multiple fixed complex systems.
2Measurement precision
If telecentric illumination and detection paths are used, then the measurement precision and imaging quality are improved, but the device complexity increases
Solution Approach 1:
The patent implements telecentric optical design specifically in the illumination and detection paths where precise measurement and imaging are required. By applying telecentricity locally to the critical optical paths rather than the entire system, the patent achieves high measurement precision for wafer surface inspection while avoiding unnecessary complexity in non-critical areas.
3Ease of repair
If the assembly unit is made movable for service accessibility, then the ease of repair is improved, but the device complexity increases
Solution Approach 1:
The inspection system is divided into a separate movable assembly unit that can be independently positioned and serviced. This segmentation allows service personnel to access and maintain the illumination and detection components without disassembling the entire inspection system, improving ease of repair while keeping the added complexity localized to the movable assembly rather than the whole system.
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 quality of wafer surface detection by maximizing light utilization and maintaining inspection quality while simplifying the apparatus for easy maintenance and service, ensuring reliable and high-quality inspection results.
Implementation Method 1
The apparatus incorporates telecentric illumination and detection paths for both bright field and dark field illuminations, utilizing multiple light sources and imaging optical elements
Implementation Method 2
The apparatus incorporates telecentric illumination and detection paths for both bright field and dark field illuminations, utilizing multiple light sources and imaging optical elements
Implementation Method 3
utilizing multiple light sources and imaging optical elements, along with optical fibers and casings, to optimize light delivery and detection
Implementation Method 4
optical elements of four illumination paths for a dark field illumination... imaging optical elements of each of the four illumination paths for the dark field illumination
Implementation Method 5
optical elements of at least one illumination path for a bright field illumination... imaging optical element of the at least one illumination path for the bright field illumination
Data Source
AI summary
An apparatus (1) for the optical inspection of wafers is disclosed, which comprises an assembly unit (10) which carries optical elements (30, 31, 32, 33) of at least one illumination path (3) for a bright field illumination and optical elements (50, 51, 52, 60, 61, 62, 70, 71, 72, 80, 81, 82) of at least one illumination path (5, 6, 7, 8) for a dark field illumination. The assembly unit (10) furthermore carries plural optical elements (91, 92, 93, 94, 95, 96, 97, 98, 99, 100) of at least one detection path (91, 92). An imaging optical element (32) of the at least one illumination path (3) for the bright field illumination (30), imaging optical elements (51, 61, 71, 81) of the at least one illumination path for the dark field illumination, and imaging optical elements (91, 95, 96) of the at least one detection path (9) are designed in such a way that all illumination paths (3, 5, 6, 7, 8) and all detection paths (91, 92) are telecentric.