Structured Illumination Inspection for Semiconductor Wafer Defect Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current inspection apparatuses face challenges in detecting smaller defects on semiconductor wafers due to limited optical resolution, especially with structured illumination methods that result in significant light loss and require post-image processing, making real-time high-resolution inspection difficult.
Innovation Solution
A structured illumination-based inspection apparatus utilizing a phase shift grating to generate SI patterns, combined with a time-delayed integration camera, which captures images while moving the object, reducing light loss and eliminating the need for post-processing by integrating images in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If structured illumination is used to improve optical resolution for detecting smaller defects, then measurement precision is improved, but light loss increases significantly
Solution Approach 1:
The patent applies periodic action by using a phase shift grating to generate structured illumination patterns that periodically modulate the light intensity. This periodic modulation enables enhanced optical resolution through spatial frequency encoding while maintaining higher light transmission efficiency compared to conventional structured illumination methods.
Solution Approach 2:
The patent changes the illumination parameters by using specific phase shift grating designs that alter the light distribution pattern. By adjusting the grating parameters and phase shifts, the system achieves improved resolution while optimizing light utilization, thereby reducing light loss.
2Measurement precision
If structured illumination is applied to achieve high resolution inspection, then measurement precision is improved, but device complexity increases due to post-image processing requirements
Solution Approach 1:
The patent applies preliminary action by pre-processing the light signal through the phase shift grating before it reaches the sensor. The grating performs phase encoding and spatial frequency modulation in advance, which simplifies subsequent image processing by embedding the resolution-enhancing information directly in the captured image data, eliminating complex post-processing requirements.
Solution Approach 2:
The patent extracts the complex processing requirements from the post-image processing stage by performing the resolution enhancement function within the optical path itself. The phase shift grating extracts and encodes the high-frequency information during illumination, transferring the processing burden from the digital domain back to the optical domain.
3Productivity
If conventional inspection methods are used, then device complexity is reduced, but productivity decreases due to inability to inspect smaller defects efficiently
Solution Approach 1:
The patent uses periodic action through phase shift grating-based structured illumination to enable rapid detection of smaller defects. The periodic modulation of light creates distinct spatial frequency patterns that enhance the visibility of fine defects, allowing for efficient inspection without requiring excessively complex processing or multiple measurement steps.
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 enables high-resolution, real-time inspection with reduced light loss, allowing for precise detection of defects on semiconductor wafers without the need for extensive post-processing, thereby improving inspection speed and accuracy.
Implementation Method 1
a phase shift grating (PSG) configured to convert the light beam from the light source into the SI
Implementation Method 2
a phase shift grating (PSG) configured to convert the light beam from the light source into the SI
Implementation Method 3
a beam splitter configured to cause the SI to be incident on an inspection object and to output a reflected beam from the inspection object
Implementation Method 4
a time-delayed integration (TDI) camera configured to capture images of the inspection object by detecting the reflected beam
Data Source
AI summary
Systems and methods related to a structured illumination (SI)-based inspection apparatus are described. The SI-based inspection apparatus may be capable of accurately inspecting an inspection object in real time with high resolution, while reducing the loss of light. Also described are an inspection method, and a semiconductor device fabrication method including the SI-based inspection method. The inspection apparatus may include a light source configured to generate and output a light beam, a phase shifting grating (PSG) configured to convert the light beam from the light source into the SI, a beam splitter configured to cause the SI to be incident on an inspection object and output a reflected beam from the inspection object, a stage capable of moving the inspection object and on which the inspection object is arranged, and a time-delayed integration (TDI) camera configured to capture images of the inspection object by detecting the reflected beam.