Optical Inspection Spatial Filter Array for Semiconductor Defect Detection
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Solution Overview
Problem
As semiconductor device patterns become finer and more complex, existing optical inspection methods struggle to effectively detect defects, impacting reliability and process yield.
Innovation Solution
An optical inspection apparatus is developed, featuring a spatial filter array with a movable spatial filter part that modifies the transmission region of incident light, allowing for scanning and optimization of the filter's opening based on defect data to enhance signal-to-noise ratio, combined with a control unit that adjusts the illumination and detection optical units to improve defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical inspection methods are used, then the inspection process is simple, but the defect detection ability is insufficient for fine and complex patterns
Solution Approach 1:
The inspection system is segmented into multiple specialized components: illumination optical unit with spatial filter array, objective lens unit, detection optical unit with tube lens array, and protective fluid supply part. Each segment performs a specific function to collectively improve defect detection capability for fine patterns while managing system complexity through modular design
Solution Approach 2:
The system changes optical parameters by using a spatial filter array that modifies transmission regions of incident light, and a tube lens array with different magnifications, to optimize the inspection of fine and complex patterns. The protective fluid supply part also changes the environmental parameters between the objective lens and substrate
2Measurement precision
If the spatial filter opening is fixed, then the device complexity is low, but the signal-to-noise ratio for defect detection is insufficient
Solution Approach 1:
The spatial filter array is pre-configured with multiple filters having different transmission region patterns. Before actual inspection, the appropriate spatial filter is selected and positioned to optimize the signal-to-noise ratio for the specific inspection task, avoiding the need for real-time complex adjustments during measurement
Solution Approach 2:
The spatial filter array enables dynamic adjustment of the transmission region characteristics by switching between different spatial filters. This allows the system to adapt the illumination pattern dynamically to match different inspection requirements, improving signal-to-noise ratio while maintaining manageable device complexity through discrete filter selection
3Measurement precision
If a single tube lens is used, then the device complexity is low, but the defect detection precision and adaptability are insufficient
Solution Approach 1:
The detection optical unit is segmented into multiple tube lenses arranged in an array, each with different magnifications. This segmentation allows selective use of appropriate magnification levels for different defect sizes and inspection requirements, improving overall detection precision while managing complexity through organized modular structure
Solution Approach 2:
The tube lens array provides multi-functionality by enabling the detection system to handle multiple inspection scenarios with different magnification requirements using a single integrated unit. The system can switch between different tube lenses to detect various defect types and sizes, making the inspection apparatus universally applicable to diverse inspection tasks
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 apparatus enhances inspection ability and reliability by optimizing the spatial filter's design based on defect data, improving the detection of defects on semiconductor substrates through enhanced signal-to-noise ratio and adaptive illumination control.
Implementation Method 1
a spatial filter array configured to modify a transmission region of the incident light irradiated from the light source part
Implementation Method 2
an objective lens unit disposed between the illumination optical unit and the inspection target unit
Implementation Method 3
a detection optical unit configured to receive reflective light reflected from the inspection target to thereby detect a presence or absence of a defect exists on the inspection target
Data Source
AI summary
An optical inspection apparatus includes an inspection target unit on which an inspection target is loaded, an illumination optical unit configured to irradiate incident light to the inspection target, an objective lens unit disposed between the illumination optical unit and the inspection target unit, a detection optical unit configured to receive reflective light reflected from the inspection target to thereby detect a presence or absence of a defect on the inspection target, and a control unit configured to control the illumination optical unit and the detection optical unit. The illumination optical unit includes a light source part configured to irradiate the incident light, and a spatial filter array configured to modify a transmission region of the incident light irradiated from the light source part. The spatial filter array includes a spatial filter part, and a filter movement part configured to move the spatial filter part.