Semiconductor Lead Frame with Exposed Die Pad Back Surface
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Solution Overview
Problem
Semiconductor devices with multiple components mounted side by side on a common lead frame face challenges in preventing component contact, leading to potential electrical issues and heat dissipation problems.
Innovation Solution
The semiconductor device design includes a first lead with a first die pad and a second die pad arranged orthogonally, connected by a connecting portion, where the first die pad's back surface is exposed from the sealing resin, allowing for separate mounting and heat dissipation of semiconductor elements, and using metal layers with better solder wettability to prevent solder paste flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple semiconductor chips are mounted side by side on the same lead frame island, then the device can achieve multi-functionality and higher integration, but the chips may come into contact with one another causing electrical shorts or manufacturing defects
Solution Approach 1:
The patent positions the second die pad at a different height level (z-direction) relative to the first die pad, creating a three-dimensional arrangement. This vertical separation in the thickness direction prevents lateral contact between components while maintaining electrical connectivity through the connecting portion, thus resolving the contact issue while preserving multi-functionality
Solution Approach 2:
The lead frame is divided into multiple die pads (first and second die pads) that are spatially separated and functionally independent. Each die pad can mount different semiconductor chips with different functions, allowing multi-functionality while the physical separation prevents unwanted contact between components
2Productivity
If multiple electronic components are mounted side by side on the same lead, then the device achieves higher integration density, but the components may come into contact causing manufacturing defects
Solution Approach 1:
By utilizing the thickness direction (z-axis) to position die pads at different heights, the patent achieves three-dimensional integration rather than simple two-dimensional side-by-side mounting. This increases integration density while the vertical separation provides built-in protection against placement errors causing contact
Solution Approach 2:
The connecting portion acts as an intermediary structure that electrically connects the first and second die pads while maintaining their spatial separation. This mediator enables high integration density through electrical connectivity while preventing direct contact between components mounted on different die pads
3Volume of moving object
If semiconductor chips are mounted side by side on the same lead frame, then the device achieves compact size, but heat dissipation becomes difficult due to component proximity
Solution Approach 1:
The patent arranges die pads at different heights in the thickness direction, creating vertical thermal pathways. This three-dimensional configuration allows heat to dissipate more effectively through the connecting portion and lead frame structure, preventing heat accumulation even in compact devices with multiple components
Data Source
AI summary
A semiconductor device includes: a first lead; a first semiconductor element mounted on the first lead; and a sealing resin that covers the first semiconductor element, wherein the first lead includes: a first die pad having a first main surface and a first back surface facing opposite sides to each other in a thickness direction; a second die pad arranged side by side with the first die pad in a first direction orthogonal to the thickness direction, and located on a side of the first main surface with respect to the first die pad in the thickness direction; and a connecting portion connected to the first die pad and the second die pad, and wherein the first back surface is exposed from the sealing resin.