Flat Panel Display Gate Insulating Film Etching
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Solution Overview
Problem
The existing methods for fabricating flat panel displays face challenges in achieving uniform etching and reliable contact between the data line and the transparent electrode layer due to the thickness differences and the use of thick organic gate insulating films, leading to potential contact failures.
Innovation Solution
The solution involves forming a flat panel display with a data line, an interlayer insulating film, a connecting member with stepped portions, and a gate insulating film, where the second and third contact openings are etched to expose the connecting member and gate pad, respectively, ensuring equal etching margins and preventing overetching, and using a passivation layer to protect the organic semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thick organic gate insulating film is used to protect the organic semiconductor layer from chemicals and plasma, then the protection capability is improved, but the etching uniformity deteriorates and contact reliability worsens due to insufficient etching margin
Solution Approach 1:
The gate insulating film is segmented into two distinct layers: a lower inorganic gate insulating film (first gate insulating film) and an upper organic gate insulating film (second gate insulating film). The inorganic layer provides a stable base with good etching characteristics, while the organic layer provides chemical and plasma protection. This segmentation allows the etching process to primarily affect the inorganic layer, ensuring uniformity, while the organic layer remains intact to protect the semiconductor layer.
Solution Approach 2:
The inorganic gate insulating film acts as an intermediary layer between the data line and the organic semiconductor layer. It serves as the primary etching target, absorbing the etching process and protecting the organic semiconductor layer from direct chemical exposure. The organic gate insulating film then provides additional protection on top of this intermediary layer.
2Reliability
If the thickness of the gate insulating film is increased to prevent contact failure, then the contact reliability is improved, but the etching process becomes non-uniform and overetching risks increase
Solution Approach 1:
The gate insulating film is divided into two layers with different thicknesses and materials. The inorganic layer (first gate insulating film) has a thickness of 50-150 nm and serves as the primary etching stop layer, while the organic layer (second gate insulating film) has a thickness of 50-200 nm and provides chemical protection. This segmentation allows for controlled etching depth without requiring excessive total thickness.
3Adaptability or versatility
If different etching depths are used for contact openings to data line and gate pad, then the contact structure is adapted to different thicknesses, but etching uniformity deteriorates
Solution Approach 1:
The two-layer gate insulating film structure provides universal etching characteristics across the entire substrate. Both the data line contact opening and gate pad contact opening etch through the same organic and inorganic layers to the same reference plane, achieving uniform etching depth and characteristics regardless of the underlying structure thickness variations.
Data Source
AI summary
The invention provides a flat panel display having an insulating substrate; a data line formed on the insulating substrate; an interlayer insulating film formed on the data line having a first contact opening exposing the data line; a connecting member formed in a part of the first contact opening; an interlayer insulating film around the first contact opening; a gate insulating film formed on the connecting member having a second contact opening exposing the connecting member; and an organic semiconductor layer formed on the gate insulating film.