Micro LED Chip Electrode Segmentation for Probe Positioning
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Solution Overview
Problem
The small size of micro-LED chips makes it difficult to accurately position test probes on their electrodes, leading to challenges in measuring electrical and optical properties, particularly for low current measurements which are prone to errors due to low luminance.
Innovation Solution
The micro-LED chip design includes an epitaxial layered structure with distinct electrode regions having different surface morphologies, allowing for improved positional accuracy of test probes through wire connecting regions that can be formed by metal wires, enabling precise testing and subsequent removal to maintain electrode integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the micro-LED chip size is reduced to achieve high resolution and compact integration, then the device density and color saturation are improved, but the electrode size becomes too small for accurate probe positioning during testing
Solution Approach 1:
The electrode surface is segmented into two distinct regions: a first region with a first surface morphology and a second region with a second surface morphology. This segmentation allows the probe to be positioned on the larger second region during testing, while the first region maintains the actual electrical connection, thereby resolving the contradiction between small electrode size and probe positioning accuracy
Solution Approach 2:
Different regions of the electrode surface are given different local qualities through distinct surface morphologies. The first region has a morphology suitable for electrical connection, while the second region has a morphology that facilitates probe positioning and identification. This local differentiation allows the electrode to simultaneously satisfy both the small size requirement and the probe positioning accuracy requirement
2Measurement precision
If the micro-LED chip size is reduced to achieve high resolution display, then the device compactness is improved, but the measurement time increases and measurement error increases due to low luminance
Solution Approach 1:
The second region with its distinct surface morphology acts as an intermediary that facilitates accurate probe positioning. By ensuring precise probe placement on the second region, the measurement process achieves better accuracy with fewer retries, thereby reducing both measurement error and the time required for successful measurements despite the low luminance of small micro-LED chips
Data Source
AI summary
A micro-LED chip includes an epitaxial layered structure, and first and second electrodes. The epitaxial layered structure includes first-type and second-type semiconductor layers, and a light emitting layer sandwiched therebetween. The first and second electrodes are electrically connected to the first-type and second-type semiconductor layers, respectively. The micro-LED chip has a first distinctive region on an electrode surface of the first electrode. The first distinctive region has a surface morphology different from that of an adjacent region of the electrode surface of the first electrode. A method for manufacturing a micro-LED device including at least one micro-LED chip is also provided.