Pixel Electrode Metal Layer Protrusion for Etching Damage
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Solution Overview
Problem
The existing display devices face challenges in achieving optimal electrical connection characteristics between pixel electrodes and switching elements, particularly due to damage during the dry etching process for forming openings in the insulating layers, which affects the flow of current.
Innovation Solution
The solution involves a display device design with a metal layer at the lower portion of the pixel electrode, including a protrusion and an undercut in the first insulating layer, and a pixel electrode connector that contacts the protrusion and extension through a specifically formed opening, allowing for improved electrical connection and current flow despite potential damage during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an opening is formed in the insulating layer to connect the pixel electrode and switching element, then electrical connection is achieved, but the pixel electrode may be damaged during the dry etching process
Solution Approach 1:
A metal layer is introduced as an intermediary conductive structure between the pixel electrode and switching element. This metal layer serves as a mediator that provides an alternative current path, protecting the pixel electrode from direct exposure to the etching process while maintaining electrical connection reliability.
Solution Approach 2:
The metal layer is formed beforehand to create a protective barrier that cushions the pixel electrode against potential damage during the subsequent opening formation process. This preliminary protective structure ensures that even if the pixel electrode is exposed to etching, the electrical connection remains intact through the metal layer pathway.
2Device complexity
If the pixel electrode is directly connected to the switching element through an opening, then the structure is simple, but current flow may be disrupted if the pixel electrode is damaged
Solution Approach 1:
The invention changes the material parameter of the connection structure by introducing a metal layer with different electrical and mechanical properties compared to the original pixel electrode material. This parameter change creates a more robust connection that maintains current flow continuity even when the pixel electrode undergoes structural changes during processing.
3Reliability
If a metal layer is added to protect the pixel electrode, then electrical connection reliability is improved, but device complexity increases
Solution Approach 1:
The metal layer serves multiple functions simultaneously: it acts as a protective barrier during etching, provides an alternative current pathway, and can serve as part of the overall conductive network. This multi-functionality justifies the additional layer by delivering multiple benefits from a single structural addition.
Data Source
AI summary
An exemplary embodiment of the present inventive concept provides a display device including: a substrate; a metal layer disposed on the substrate; a pixel electrode disposed on the metal layer and including a protrusion overlapping the metal layer; a first insulating layer covering the metal layer and the pixel electrode; an extension of a drain electrode disposed on the first insulating layer and overlapping a portion of the protrusion; a second insulating layer covering the first insulating layer and the extension; and a pixel electrode connector disposed on the second insulating layer and overlapping the protrusion and the extension, wherein the first insulating layer and the second insulating layer include a first opening exposing an upper surface of the protrusion and an upper surface of the extension, and the pixel electrode connector contacts the upper surface of the extension and the upper surface of the protrusion through the first opening.