Sealing Layer Prevents Etchant Corrosion in TFT Wiring
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Solution Overview
Problem
In thin-film transistor display devices, the risk of etchant penetration through contact holes during pixel electrode patterning can lead to corrosion of the metal wiring layer, increasing electrical resistance and reducing operation stability.
Innovation Solution
A configuration that includes a passivation layer with contact holes over the lead wiring layer, a continuous connecting wiring layer across the passivation layer, a sealing layer covering the connecting wiring layer within the contact holes, and an upper sealing layer to prevent etchant penetration and protect the connecting wiring layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a contact hole is opened in the passivation layer to connect the connecting wiring layer pattern to the metal wiring layer pattern, then electrical connection is achieved, but etchant can penetrate through the contact hole to corrode the metal wiring layer pattern
Solution Approach 1:
The patent introduces a sealing layer pattern as an intermediary substance that fills the contact hole between the connecting wiring layer pattern and metal wiring layer pattern. This sealing layer acts as a mediator that allows electrical connection to be achieved while simultaneously preventing etchant from penetrating through the contact hole to corrode the metal wiring layer pattern, thus resolving the contradiction between connection stability and corrosion prevention
Solution Approach 2:
The sealing layer pattern is formed in advance to prevent the harmful action of etchant penetration. By pre-filling the contact hole with the sealing layer pattern before etching processes, the patent proactively counteracts the potential corrosion damage, ensuring that the metal wiring layer pattern remains protected while maintaining electrical connectivity
2Ease of manufacture
If the connecting wiring layer pattern is made thin to reduce manufacturing complexity, then ease of manufacture is improved, but the pattern becomes more vulnerable to etchant penetration and corrosion
Solution Approach 1:
The patent creates a composite protective structure by combining the connecting wiring layer pattern with the sealing layer pattern. This composite configuration allows the connecting wiring layer pattern to remain thin for manufacturing ease while the added sealing layer pattern provides enhanced corrosion resistance, effectively resolving the contradiction between manufacturing simplicity and corrosion protection
Data Source
AI summary
A display device including: a lead wiring layer pattern 207, made from metal, that extends outside a region 10A on a substrate in which a light-emitter is present; a passivation layer 216; a contact hole 216a in the passivation layer 216 outside the region 10A in a position over the lead wiring layer pattern 207 in plan view; a connecting wiring layer pattern 237 that is continuous across the passivation layer 216, an inner circumference of the contact hole 216a, and the lead wiring layer pattern 207 in the contact hole 216a; a sealing layer 217 covering a portion of the connecting wiring layer pattern 237 in the contact hole 216a; and an upper sealing layer pattern 219 covering the sealing layer pattern 217 that is above the connecting wiring layer pattern 237.