Display Substrate Organic Layer Hole Pattern for Parasitic Capacitance
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Solution Overview
Problem
The existing display substrate manufacturing process faces issues with parasitic capacitance, under-cut generation, and increased manufacturing costs due to the use of organic layers, which lead to reduced reliability and increased processing time.
Innovation Solution
A display substrate design that includes a base substrate, switching element, protecting layer, and organic layer with strategically formed holes to reduce parasitic capacitance and under-cut, along with a method of manufacturing that uses fewer masks to pattern the organic layer, thereby improving the connection between pixel electrodes and reducing disconnection risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an organic layer is added to increase the distance between the pixel electrode and the gate line or data line, then parasitic capacitance is reduced, but the number of masks increases and manufacturing cost increases
Solution Approach 1:
The patent combines the organic layer patterning with the pixel electrode patterning into a single mask process. The organic layer is patterned using the same mask that defines the pixel electrode, eliminating the need for a separate mask step while maintaining the distance-increasing function that reduces parasitic capacitance.
Solution Approach 2:
The organic layer serves multiple functions: it acts as an insulating layer to reduce parasitic capacitance, as a structural support layer during processing, and as a pattern definition layer that is simultaneously used for pixel electrode formation. This multi-functionality reduces the overall number of masks required.
2Ease of operation
If the organic layer and protecting layer are patterned to form a contact hole, then access to the drain electrode is achieved, but an under-cut is generated and the pixel electrode may be disconnected
Solution Approach 1:
The patent performs a preliminary ashing process on the organic layer before forming the contact hole to the drain electrode. This preliminary action removes potential under-cuts in advance, ensuring that when the contact hole is formed, the pixel electrode remains properly connected without disconnection risks.
Solution Approach 2:
The patent uses a selective ashing process that quickly removes the organic layer material at the contact hole location without causing excessive under-cut. By controlling the ashing conditions and duration, the process rushes through the removal step efficiently while minimizing the harmful under-cut effect that would otherwise disconnect the pixel electrode.
3Reliability
If the organic layer is subjected to an ashing process to remove the under-cut, then the under-cut is reduced, but the processing time increases and the surface of the organic layer becomes rough
Solution Approach 1:
The patent applies ashing selectively only to specific regions where under-cuts would form, rather than treating the entire organic layer uniformly. This localized approach removes under-cuts at contact hole locations while preserving the surface quality and reducing overall processing time compared to full-layer ashing.
Data Source
AI summary
A display substrate includes a base substrate, a switching element, a protecting layer, an organic layer, a first pixel electrode and a second pixel electrode. The switching element is on the base substrate, and includes a gate electrode, a source electrode and a drain electrode. The protecting layer is on the switching element, and includes a first hole exposing the drain electrode. The organic layer is on the protecting layer, and includes a second hole which exposes a side surface of the protecting layer which defines the first hole and exposes a top surface of the protecting layer which is adjacent to the side surface of the protecting layer. The first pixel electrode is on the organic layer. The second pixel electrode overlaps the first pixel electrode, and is electrically connected to the drain electrode via the first and second holes.