Face-down LED CSP with Internal Wiring and Resin Support
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Solution Overview
Problem
Face-down light-emitting devices face limitations in size reduction and luminous efficiency due to the need for bonding wires in face-up configurations and the challenge of supporting thin, weak semiconductor light-emitting elements, which restricts further miniaturization and performance enhancement.
Innovation Solution
A light-emitting device configuration featuring a semiconductor light-emitting element with a first and second resin layer and metallic layers, where the second metallic layer's upper surface is exposed and partially lower than the second resin layer's upper surface, allowing for internal wiring and improved mechanical support, enabling efficient electrical connections and reduced size while preventing adhesive leakage during mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bonding wires are used to connect semiconductor light-emitting elements and leads, then electrical connections are achieved, but the device size cannot be reduced further due to the need to locate bonding wires partially outside the semiconductor light-emitting elements
Solution Approach 1:
The patent inverts the conventional connection approach by using face-down mounting where the semiconductor light-emitting element is mounted with its light-emitting surface facing the mounting substrate, rather than facing upward. This inversion allows the element to be connected to the mounting substrate through its lower surface, eliminating the need for bonding wires that extend outside the element boundaries and enabling further size reduction.
Solution Approach 2:
The patent transitions from planar bonding wire connections to three-dimensional internal wiring structures. By forming conductive patterns and wiring layers within the mounting substrate itself, the connection path moves from the external plane to the internal depth dimension, allowing compact integration without requiring additional space for bonding wires outside the element.
2Volume of moving object
If growth substrates are removed or reduced in thickness to advance size reduction, then device size is reduced, but the semiconductor light-emitting elements lose mechanical support and strength
Solution Approach 1:
The patent introduces a resin layer as an intermediary support structure between the mounting substrate and the semiconductor light-emitting element. This resin layer provides the necessary mechanical support and strength to the thin semiconductor elements after the growth substrate is removed, while still allowing for compact device integration and size reduction.
Solution Approach 2:
The patent changes the mechanical support parameter from relying on the growth substrate to relying on the resin layer with appropriate mechanical properties. By selecting and designing the resin layer with suitable thickness, composition, and mechanical characteristics, the element strength is maintained even without the growth substrate.
3Reliability
If internal wiring with metal pillars is formed to penetrate the resin layer, then electrical connections are achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the formation of the resin layer and the internal wiring structure into an integrated manufacturing process. The resin layer is formed first, then conductive patterns and wiring layers are formed within or on the resin layer, combining multiple functions into a unified structure that simplifies the overall manufacturing process while ensuring reliable electrical connections.
Data Source
AI summary
A light-emitting device includes a semiconductor light-emitting element, a first resin layer, a first metallic layer, a second resin layer, and a second metallic layer. The semiconductor light-emitting element includes a semiconductor stacked body and an electrode provided on one side of the semiconductor stacked body. The second resin layer is provided on the first resin layer and has a lower surface in contact with the first resin layer and an upper surface opposite to the lower surface. The second metallic layer is provided in the second resin layer and has a metallic lower surface and a metallic upper surface opposite to the metallic lower surface. The metallic upper surface is exposed from the second resin layer. The metallic upper surface of the second metallic layer is at least partially lower in height from the semiconductor stacked body than the upper surface of the second resin layer.