Package Structure With Exposed Lead Frame Surfaces
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Solution Overview
Problem
The increasing density of electronic devices due to miniaturization poses challenges in heat dissipation and short circuit prevention, particularly in power transistors that generate high heat and handle high-power signals.
Innovation Solution
A package structure design that includes an encapsulant and a lead frame structure with exposed surfaces for efficient heat dissipation, where the minimal distance between electrode exposed surfaces is greater than the distance between the electrodes, preventing electric arcs and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the lead frame is designed with compact electrode arrangement to reduce device size, then device density increases, but heat dissipation becomes insufficient and short circuit risk increases
Solution Approach 1:
The patent extends the lead frame structure in the vertical dimension by creating exposed surfaces on opposite sides of the lead frame. This allows heat to be dissipated from multiple directions (top and bottom surfaces) rather than relying solely on lateral heat transfer, effectively increasing heat dissipation capability without increasing the horizontal footprint of the device.
Solution Approach 2:
The lead frame is divided into distinct segments with specific functions: electrodes for electrical connection and exposed surfaces for heat dissipation. This segmentation allows the heat dissipation function to be separated from the electrical connection function, enabling independent optimization of both aspects - compact electrode arrangement for small size and extended exposed surfaces for effective heat dissipation.
2Volume of moving object
If electrodes are positioned closer together to reduce device dimensions, then device size decreases, but the risk of electric arc and short circuit increases
Solution Approach 1:
The patent introduces a spatial separation in the vertical dimension by positioning exposed surfaces on opposite sides of the lead frame. This creates sufficient clearance between electrical components in the vertical direction, preventing electric arcs while allowing horizontal compactness. The exposed surfaces are spaced apart in the thickness direction of the lead frame, establishing a safety dimension that prevents short circuits.
Solution Approach 2:
The lead frame structure itself acts as an intermediary barrier between the electrodes. By positioning exposed surfaces on opposite sides of the lead frame with sufficient spacing, the lead frame provides physical separation and insulation that prevents direct electrical discharge between electrodes, even when they are positioned close together horizontally.
3Temperature
If the lead frame structure is optimized for heat dissipation with extended surfaces, then heat dissipation improves, but device complexity increases
Solution Approach 1:
The lead frame is designed to perform multiple functions simultaneously: it provides electrical connection through the electrodes, structural support for the semiconductor device, and heat dissipation through the exposed surfaces. This multi-functionality eliminates the need for separate heat sink components, reducing overall device complexity while maintaining effective heat dissipation. The same structure that holds the electrodes also serves as the heat dissipation pathway.
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 effectively transfers heat from the active component while maintaining sufficient distance to prevent short circuits, addressing both heat dissipation and short circuit issues in high-power signal processing.
Implementation Method 1
since the first and second lead frame segments respectively have first and second exposed surfaces exposed outside the encapsulant, the heat of the active component may be transferred out of the encapsulant
Data Source
AI summary
A package structure includes an encapsulant, an active component, a first lead frame segment, and a second lead frame segment. The active component is encapsulated within the encapsulant and includes first and second electrodes. The first and second electrodes are respectively disposed on and electrically connected to the first and second lead frame segments. The first and second lead frame segments respectively have first and second exposed surfaces. The first exposed surface and the first electrode are respectively located on opposite sides of the first lead frame segment. The second exposed surface and the second electrode are respectively located on opposite sides of the second lead frame segment. The first and second exposed surfaces are exposed outside the encapsulant. A minimal distance from the first electrode to the second electrode is less than a minimal distance from the first exposed surface to the second exposed surface.