Wearable Display Electrode Contact Without CMP
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Solution Overview
Problem
Existing display devices face challenges in improving reliability due to process dispersion defects during chemical mechanical polishing (CMP) and inadequate contact areas between reflective electrodes and anode electrodes, which affect the overall performance and durability of wearable electronic devices.
Innovation Solution
A display device design with a planarization layer formed through an etching process, eliminating the need for CMP, and ensuring direct contact between reflective electrodes and anode electrodes, enhanced by a buffer pattern and specific separation distances, thereby increasing contact area and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If chemical mechanical polishing (CMP) is used to form the planarization layer, then a flat upper surface is achieved, but process dispersion defects occur reducing reliability
Solution Approach 1:
The patent removes the CMP process from the manufacturing sequence and replaces it with an etching process. The planarization layer is formed by etching the insulating material layer to expose the reflective electrode, eliminating the harmful effects of CMP while maintaining the required flat upper surface for subsequent electrode formation.
Solution Approach 2:
The patent substitutes the mechanical CMP process with a chemical etching process. Instead of mechanically polishing the insulating material layer to achieve flatness, the etching process chemically removes material to expose the reflective electrode, replacing mechanical action with chemical action to improve reliability.
2Reliability
If the anode electrode is positioned to ensure direct contact with the reflective electrode, then contact area is increased, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent performs preliminary action by forming the via hole in the planarization layer before depositing the anode electrode. The via hole is pre-formed with controlled dimensions and position to ensure proper exposure of the reflective electrode. This preliminary structuring enables subsequent direct contact between the anode electrode and reflective electrode while maintaining manufacturing precision through controlled via hole formation rather than relying on precise electrode positioning.
Data Source
AI summary
A display device may include first, second, and third sub-pixels including a reflective electrode above a base layer, a planarization layer above the reflective electrode, having a flat upper surface, defining a via exposing a portion of the reflective electrode, and including first and second side surfaces facing each other with the via therebetween, an anode electrode above the planarization layer, above an area of the reflective electrode exposed by the via, and directly connected to the reflective electrode, a light-emitting structure above the anode electrode, and a cathode electrode above the light-emitting structure, wherein the first sub-pixel further includes a buffer pattern between the base layer and the reflective electrode, and wherein a separation distance between the anode electrode and the reflective electrode in the first sub-pixel is less than a separation distance between the anode electrode and the reflective electrode in the second and third sub-pixels.