Stacked Micro-LED Pixel Structure With Etch-Stop Electrode Contacts
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Solution Overview
Problem
The existing micro-LED display panel structure has poor space utilization, requiring smaller chip sizes that affect conversion efficiency, and involves complex manufacturing processes due to the need for separate transfers of red, green, and blue micro-LED chips.
Innovation Solution
A micro-LED design where the red, green, and blue light-emitting diode chips are arranged in a vertical stacking manner, utilizing an epitaxial structure with multiple stack layers and etch stop layers, and electrodes that contact the etch stop layers to avoid over-etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If red, green, and blue micro-LED chips are arranged in a horizontal direction (juxtaposed on the panel), then the manufacturing process requires separate transfers for each color, but this increases the number of process steps and reduces space utilization
Solution Approach 1:
The patent transitions from a horizontal arrangement of micro-LED chips to a vertical stacking configuration. Multiple micro-LED chips of different colors (red, green, blue) are stacked vertically within the same pixel area, utilizing the vertical dimension to increase space utilization while simplifying the manufacturing process by enabling simultaneous transfer of all color chips in one step
2Area of stationary object
If chip size is reduced to fit more chips in the same pixel area, then space utilization improves, but conversion efficiency of the chip deteriorates
Solution Approach 1:
By stacking micro-LED chips vertically, the patent allows each chip to maintain its original, larger size for optimal conversion efficiency while still fitting multiple chips within a single pixel area through vertical arrangement, thus resolving the conflict between space utilization and conversion efficiency
3Reliability
If etching is performed to form electrodes, then electrical connection is achieved, but over-etching may occur damaging the active layer
Solution Approach 1:
The patent introduces an etch stop layer positioned between the active layer and the electrode formation region. This etch stop layer is deposited beforehand to prevent over-etching during the electrode formation process, thereby protecting the active layer from damage while ensuring proper electrical connection
Solution Approach 2:
The etch stop layer serves as an intermediary layer that mediates between the etching process and the active layer. It provides a controlled stopping point for the etching process, preventing direct contact between the etchant and the active layer, thus ensuring manufacturing precision while achieving reliable electrical connection
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances space utilization and display effect while maintaining pixel size, avoids conversion efficiency issues from chip miniaturization, and simplifies the manufacturing process by reducing the number of transfer steps.
Implementation Method 1
The first stack layer, the second stack layer and the third stack layer are configured to respectively emit three different light-emitting colors
Data Source
AI summary
A micro light-emitting diode includes a first stacked layer, a second stacked layer, a third stacked layer, a bonding layer, at least one etch stop layer, and a plurality of electrodes. The second stacked layer is disposed between the first stacked layer and the third stacked layer. The first stacked layer includes a first active layer. The second stacked layer includes a second active layer. The third stacked layer includes a third active layer. The bonding layer is disposed between the second stacked layer and the third stacked layer. The at least one etch stop layer is at least disposed between the first active layer and the second active layer. The plurality of electrodes are respectively electrically connected with the first stacked layer, the second stacked layer, and the third stacked layer. At least one electrode of the plurality of electrodes contacts the etch stop layer.