Power Semiconductor Package Layout for Isolation and Heat Dissipation
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Solution Overview
Problem
Power semiconductor packages face challenges in electrical isolation and heat dissipation, as elaborate isolation concepts increase costs and thermal resistance, while conductive components provide better cooling but higher thermal resistance.
Innovation Solution
A power semiconductor package design featuring a leadframe with separated die pads, where one die pad is exposed and the other is completely covered with electrically insulating material, encapsulated in a molded body to provide efficient heat dissipation and electrical isolation, reducing material consumption and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If components are electrically isolated from external parts, then electrical safety is improved, but thermal resistance increases and heat dissipation capability deteriorates
Solution Approach 1:
The leadframe is segmented into multiple die pads (first die pad, second die pad, third die pad) with different electrical potentials. Each die pad is electrically isolated from external parts through separate insulation structures, allowing independent thermal management for each segment. This enables heat dissipation pathways to be optimized for each electrical potential level without compromising electrical isolation.
Solution Approach 2:
An electrically insulating material is introduced as an intermediary between the second die pad (with different electrical potential) and external parts. This insulating material provides electrical isolation while the patent designs alternative thermal pathways (through the leadframe and molded body) to maintain heat dissipation capability without direct thermal contact through the insulation layer.
2Reliability
If elaborate isolation concepts are used, then electrical isolation is improved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent combines multiple isolation functions into a single molded body structure. The molded body encapsulates the leadframe and semiconductor devices while providing electrical isolation through its insulating material. This merging of structural support, encapsulation, and electrical isolation functions reduces the number of separate components and simplifies manufacturing compared to using separate isolation structures.
Solution Approach 2:
The molded body serves multiple functions simultaneously: it provides mechanical support for the leadframe, encapsulates the semiconductor devices for protection, and provides electrical isolation between different potential levels and external parts. This multi-functionality reduces the need for separate dedicated isolation components, thereby reducing manufacturing complexity.
3Temperature
If conductive components are used for heat dissipation, then thermal resistance is reduced, but electrical isolation capability deteriorates
Solution Approach 1:
Different regions of the leadframe and package structure have different electrical properties. The first die pad region is designed with direct thermal pathways through the leadframe and molded body for efficient heat dissipation. The second die pad region uses electrically insulating material for isolation, while still providing thermal pathways through the leadframe structure. This local differentiation allows optimization of thermal and electrical properties in different areas simultaneously.
Data Source
AI summary
A power semiconductor package comprises a leadframe comprising a first die pad, a second die pad and a plurality of external contacts. The first and second die pads are separated by a first gap. A power semiconductor die is arranged on and electrically coupled to a first side of the first die pad. A diode is arranged on and electrically coupled to a first side of the second die pad. A molded body encapsulates the power semiconductor die and the diode, the molded body having a first side, an opposite second side and lateral sides connecting the first and second sides. A second side of the first die pad is exposed from the second side of the molded body. A second side of the second die pad is completely covered by an electrically insulating material.