Synchronized Substrate Transfer and Image Capture for Semiconductor Defect Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In photolithography processes, macro defect inspection in semiconductor manufacturing is hindered by reduced throughput and space requirements due to the need for a dedicated defect inspection device, which is inefficient when the transfer speed of substrates does not match the image capture cycle of the image pickup device.
Innovation Solution
Synchronizing the drive of the transfer member with the image pickup unit to capture precise images of substrates being transferred, using a controller to manage the image capture based on driving signals or encoder feedback, allowing for precise image capture without additional space or dedicated inspection devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dedicated defect inspection device is used, then inspection accuracy is improved, but throughput is reduced due to transfer time and space requirements
Solution Approach 1:
The patent merges the defect inspection function with the existing substrate transfer system by installing the image pickup device on the transfer member or transfer path. This allows inspection to occur during the transfer process itself, eliminating the need for a separate dedicated inspection device and its associated transfer operations, thereby maintaining inspection accuracy while improving throughput.
Solution Approach 2:
The transfer member or transfer path is given a dual function: it both transfers the substrate and serves as the inspection platform. By making the transfer system multi-functional, the patent eliminates redundant equipment and processes, allowing continuous operation without sacrificing inspection quality.
2Productivity
If image pickup is performed during substrate transfer, then throughput is improved, but image precision deteriorates due to speed mismatch between transfer and capture
Solution Approach 1:
The patent employs feedback control by using encoder signals from the transfer member's drive unit to control the image pickup timing. The encoder provides real-time position feedback, allowing the system to synchronize image capture with the substrate's position and transfer speed, ensuring precise images are captured regardless of transfer velocity variations.
Solution Approach 2:
The patent makes the image pickup system dynamic by synchronizing its operation with the variable speed of the transfer member. Instead of using a fixed capture cycle, the system adapts its timing based on the actual transfer speed, allowing precise image capture even when transfer conditions change.
Data Source
AI summary
In the present invention, an image of a substrate is picked up by an image pickup unit with the substrate being held by a transfer member. A drive unit for the transfer member is controlled by a driving signal from a first controller. A driving signal outputted to the first controller is outputted also to a second controller so that the second controller controls the image pickup unit based on the driving signal, thereby synchronizing drive of the transfer member with the image pickup by the image pickup unit. According to the present invention, the throughput in performing a defect inspection for the substrate is improved and a precise image is captured and subjected to accurate inspection.