LED Current Spreading Bond Pads for High Aspect Ratio Packaging
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Solution Overview
Problem
Existing semiconductor light emitting diodes (LEDs) face challenges in providing effective current spreading structures for high aspect ratio devices, which are difficult to package and require efficient contact mechanisms, especially when the aspect ratio changes for specific applications.
Innovation Solution
The implementation of current spreading bond pad structures with multiple bond pads and fingers arranged in specific patterns, including alphanumeric characters, to convey information about operating properties like color temperature and luminous intensity, and to facilitate scalable and cost-effective fabrication for various dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bond pad structure is used for conventional LEDs, then the structure is simple and easy to manufacture, but it becomes inadequate for high aspect ratio LEDs requiring effective current spreading
Solution Approach 1:
The bond pad structure is segmented into multiple bond pads (at least three) arranged along one edge of the LED, with each bond pad connected to the LED contact through separate current spreading fingers. This segmentation allows current to distribute more effectively across the high aspect ratio LED structure while maintaining manufacturability through standardized fabrication processes.
Solution Approach 2:
The bond pad structure transitions from a conventional single-point contact to a multi-point distributed contact system. The current spreading fingers extend from the bond pads across the LED surface in specific patterns (including alphanumeric characters), creating a two-dimensional current distribution network that effectively addresses the high aspect ratio geometry.
2Reliability
If multiple bond pads and current spreading fingers are implemented, then current spreading improves, but manufacturing complexity increases
Solution Approach 1:
The current spreading fingers serve multiple functions: they provide electrical current distribution paths, define alphanumeric character patterns for device identification, and maintain structural integrity across the LED surface. This multi-functionality reduces the need for separate manufacturing steps while achieving both current spreading and information encoding.
Solution Approach 2:
The bond pad structure and current spreading fingers are integrated into a single fabrication process. The same metal layers and patterning steps that create the current spreading paths also form the alphanumeric character patterns, combining multiple functions into one manufacturing sequence and reducing overall complexity.
3Ease of operation
If bond pads are positioned along one edge only, then packaging becomes easier, but current distribution may be limited
Solution Approach 1:
While bond pads are positioned along one edge to facilitate packaging, the current spreading fingers extend across the LED surface in multiple directions, creating a two-dimensional current distribution network. This allows current to reach all areas of the high aspect ratio LED effectively while maintaining the simplified edge-aligned bond pad configuration for easy packaging.
Solution Approach 2:
The bond pad structure uses asymmetric positioning along one edge rather than symmetric distribution across the LED. This asymmetric configuration optimizes packaging accessibility while the current spreading fingers compensate by creating extended current paths that ensure uniform current distribution across the entire LED active area.
Data Source
AI summary
A light emitting device includes a diode region comprising a first face and opposing edges, and a bond pad structure comprising at least three bond pads along only one of the opposing edges of the first face.