AMOLED Storage Capacitor via Single Patterning Process
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Solution Overview
Problem
AMOLED display substrates face challenges due to parasitic capacitance, which requires a large storage capacitor to ensure normal display function, and existing fabrication processes are complex and costly.
Innovation Solution
The method involves forming a first and second storage capacitor in parallel, with the first electrode made of conductor material through a single patterning process, simplifying the fabrication and reducing costs, and using a thin film transistor with an etch stop structure to enhance capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large storage capacitor is used to compensate for parasitic capacitance, then display function reliability is improved, but device area and complexity increase
Solution Approach 1:
The patent combines the storage capacitor with the transistor structure by using the transistor's source or drain electrode as one electrode of the storage capacitor. This integration eliminates the need for a completely separate capacitor structure, thereby maintaining reliable display function while reducing device complexity and area.
Solution Approach 2:
The transistor electrode serves dual purposes: it functions as both the transistor's source/drain electrode and as an electrode for the storage capacitor. This multi-functionality approach allows the same structural element to fulfill multiple electrical functions, reducing overall device complexity while ensuring proper display operation.
2Manufacturing precision
If conventional multi-step patterning process is used, then manufacturing precision is improved, but fabrication complexity and cost increase
Solution Approach 1:
The patent merges the patterning of the transistor active layer and the storage capacitor electrode into a single patterning step. By forming both structures simultaneously using one photoresist layer and one etching process, the method maintains adequate manufacturing precision while significantly reducing fabrication complexity and the number of mask alignements required.
Solution Approach 2:
The patent designs the pattern layout such that the storage capacitor electrode pattern is defined during the same patterning step as the transistor active layer. This preliminary integration of the capacitor pattern design into the transistor fabrication process eliminates subsequent separate patterning steps, reducing overall process complexity.
Data Source
AI summary
The present disclosure provides an active-matrix organic light emitting diode display substrate, a method for fabricating the display substrate and a display device. The active-matrix organic light emitting diode display substrate includes two storage capacitors connected in parallel, an active layer of TFT and an electrode of the new added storage capacitor are formed through a single patterning process, and the electrode is made of conductor material.