Dual Down-Set QFN Terminals for External Passive Mounting
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Solution Overview
Problem
Semiconductor packages face challenges in reducing size without increasing costs, particularly for quad flat no lead (QFN) packages, as relocating passive components externally is not economically viable with existing methods.
Innovation Solution
A semiconductor package design featuring dual down-set conductive terminals and externally mounted passive components, where conductive terminals extend from die pads and are exposed through the mold compound, allowing for reduced package size by relocating components to the top surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If passive components are relocated externally to reduce package size, then package size is reduced, but manufacturing cost increases
Solution Approach 1:
The conductive terminals are configured with multiple down-sets that extend vertically downward from the die pad level, creating a multi-level three-dimensional structure. This vertical dimensionality allows external passive components to be mounted on the top surface at different heights, enabling compact packaging while maintaining electrical connectivity through the down-set terminals that reach lower levels.
Solution Approach 2:
The conductive terminals are divided into multiple down-sets rather than being single continuous structures. Each down-set can be independently formed and positioned, allowing flexible routing of electrical signals to external components while optimizing space utilization and maintaining cost-effective manufacturing processes.
2Adaptability or versatility
If conductive terminals are extended with multiple down-sets, then external component mounting is enabled, but device complexity increases
Solution Approach 1:
The multiple down-sets of conductive terminals serve multiple functions: they provide electrical connectivity between the semiconductor die and external passive components, establish reference planes for signal integrity, and enable mounting surfaces for various external components. This multi-functionality reduces the need for separate structures, thereby managing complexity while enhancing versatility.
3Manufacturing precision
If distal ends of conductive terminals are horizontally aligned, then manufacturing precision is improved, but package flexibility is reduced
Solution Approach 1:
While the distal ends of the conductive terminals are horizontally aligned to facilitate precise manufacturing and assembly, the internal structure of the terminals with multiple down-sets allows for dynamic routing of electrical signals. This alignment provides a stable reference for manufacturing processes while the multi-level down-set configuration enables flexible signal distribution to different external components.
Data Source
AI summary
In some examples, a semiconductor package comprises a first die pad having a first top surface and a first bottom surface opposing the first top surface and a second die pad in horizontal alignment with the first die pad, the second die pad having a second top surface and a second bottom surface opposing the second top surface, a gap separating the first and second die pads. The package comprises a semiconductor die electrically coupled to the first and second bottom surfaces and extending across the gap, the semiconductor die having a device side including circuitry formed therein, the device side facing away from the first and second die pads. The package comprises a first conductive terminal extending from a lateral surface of the first die pad and away from the first die pad, the first conductive terminal having multiple down-sets. The package comprises a second conductive terminal extending from a lateral surface of the second die pad and away from the second die pad, the second conductive terminal having multiple down-sets. The package comprises a third conductive terminal having fewer down-sets than the first and second conductive terminals and extending from below the first die pad and away from the first die pad. The package comprises a bond wire coupling the device side of the semiconductor die to the third conductive terminal. The package comprises a mold compound covering the semiconductor die and the bond wire, the first and second die pads exposed to an exterior of the mold compound through a top surface of the mold compound. The package comprises a passive electrical component external to the mold compound and having a first electrical contact coupled to the first die pad and having a second electrical contact coupled to the second die pad. The first, second, and third conductive terminals include distal ends that are exposed through a common side surface of the mold compound, the distal ends in horizontal alignment with each other.