TFT Substrate Defect Repair Automation via Electric-Optical Matching
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Solution Overview
Problem
Current methods for defect repair in TFT substrates, particularly for organic EL and liquid crystal displays, are inefficient due to high tact time and increased investment costs, as they struggle to automate defect repair for wiring patterns beyond TFTs and often fail to selectively repair critical defects, leading to prolonged repair times and low success rates.
Innovation Solution
A method and system that combines electric and optical inspections to identify and grade critical defects in TFT substrates, allowing for precise matching and targeted repair procedures, reducing tact time by focusing on only the critical defects causing electric faults and optimizing repair strategies based on defect position and type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If automatic repair method using pattern matching for TFT shape is used, then repair automation is improved for TFT defects, but repair capability is lost for wiring pattern defects other than TFT
Solution Approach 1:
The inspection system is designed to perform multiple functions: it can identify both TFT defects and wiring pattern defects (including electric short circuits and disconnections) using the same automated platform. The system integrates pattern matching for TFT shapes with electric property measurement and optical inspection for wiring patterns, creating a universal defect detection and repair system that handles various defect types without requiring separate manual processes.
2Reliability
If all defects are repaired based on optical inspection results, then defect coverage is improved, but repair tact time is significantly increased
Solution Approach 1:
The system applies different inspection and repair strategies to different defect types and locations. Critical defects (electric short circuits and disconnections in wiring patterns) are identified through electric property measurements and targeted for repair, while non-critical defects are either excluded from repair or handled differently. This localized approach ensures that repair resources are concentrated on defects that truly affect device functionality, reducing unnecessary repair time while maintaining reliability.
Solution Approach 2:
Instead of repairing all detected defects, the system performs partial action by selectively repairing only the critical defects that affect electric properties. The electric property measurement step identifies which defects are functionally significant, allowing the system to omit repair of non-critical defects that would otherwise consume valuable tact time. This partial repair strategy optimizes the balance between reliability and productivity.
3Extent of automation
If repair procedure selection is based only on relative position of defect, then automation is simplified, but selection success rate is lowered and immense database is demanded
Solution Approach 1:
The system replaces the mechanical approach of simple position-based lookup with a more sophisticated measurement and analysis system. Electric property measurements (conductivity, resistance) are taken at multiple locations, and the system automatically analyzes this data to identify defects and determine appropriate repair procedures. This substitution of physical measurement and automated analysis for simple positional matching improves selection accuracy while maintaining automation, eliminating the need for immense databases.
Data Source
AI summary
A method of manufacturing a substrate formed with a plurality of wiring patterns on a base, includes: a first inspection step of identifying a faulty wiring pattern having electric short circuit or disconnection by performing an electric inspection respectively for the plurality of wiring patterns; a second inspection step of examining a relative position of a defect on the base and at least one of a type and a size of the defect by an optical inspection; a matching step of matching a result of the first inspection step with a result of the second inspection step, and identifying a critical defect having electric short circuit or disconnection; and a third inspection step of examining a relative position in a pixel and an effective range of the critical defect by an optical inspection.