Die Pad Offset Structure for Creepage and Heat Dissipation
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Solution Overview
Problem
The existing semiconductor devices face a reduction in insulation withstand voltage due to a short creepage distance between the pad reverse surface and the fastening member, which is exacerbated by the exposure of the pad reverse surface from the sealing resin, leading to decreased heat dissipation.
Innovation Solution
The semiconductor device incorporates a die pad with a penetration portion and a sealing resin configuration that offsets the second portion of the die pad, increasing the creepage distance while maintaining effective heat dissipation by ensuring sufficient mounting surface area for the semiconductor element and reducing thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the pad reverse surface is exposed from the sealing resin to suppress degradation of heat dissipation, then heat dissipation is improved, but the creepage distance from the reverse surface of the pad to the fastening member becomes short, resulting in decreased insulation withstand voltage
Solution Approach 1:
The die pad is divided into a first portion and a second portion that are offset in the planar direction (second direction orthogonal to the first direction). This spatial offset arrangement increases the creepage distance between the exposed reverse surface of the first portion and the fastening member inserted through the sealing resin, while still allowing the reverse surface to remain exposed for heat dissipation. The penetration portion in the second portion provides the fastening path through the sealing resin.
2Reliability
If the second portion of the die pad is offset from the first portion in the planar direction, then the creepage distance is increased, but the mounting surface area for the semiconductor element may be reduced
Solution Approach 1:
The die pad is segmented into a first portion and a second portion with different functions. The first portion provides the mounting surface for the semiconductor element and has its reverse surface exposed for heat dissipation. The second portion contains the penetration portion for the fastening member and is offset from the first portion to increase creepage distance. This segmentation allows both heat dissipation and insulation requirements to be satisfied simultaneously.
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 configuration enhances insulation withstand voltage while effectively suppressing a reduction in heat dissipation, ensuring reliable operation and improved reliability of the semiconductor device.
Implementation Method 1
a sealing resin covering the semiconductor element, the sealing resin having an attachment portion that penetrates in a first direction and is surrounded by the penetration portion as viewed in the first direction
Implementation Method 2
a die pad having a penetration portion that penetrates in a first direction... ensuring sufficient mounting surface area for the semiconductor element and reducing thermal resistance
Data Source
AI summary
A semiconductor device comprises a die pad having a penetration portion that penetrates in a first direction, a semiconductor element bonded to the die pad and a sealing resin covering the semiconductor element, the sealing resin having an attachment portion that penetrates in the first direction and is surrounded by the penetration portion as viewed in the first direction. The die pad includes a first portion having a reverse surface that faces the first direction, and a second portion having the penetration portion and connected to the first portion. The second portion is offset on one side of a second direction with respect to the first portion. The reverse surface is exposed from the sealing resin. The second portion is covered with the sealing resin.