Inverted Semiconductor Package with Dual Bending Drain Clips
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Solution Overview
Problem
Existing semiconductor packages face challenges in heat dissipation and mechanical reliability, particularly in thinner designs and larger form factors, where increased thickness to prevent wire shorting can lead to package cracking and detachment issues during singulation.
Innovation Solution
A semiconductor device design featuring a leadframe with dual bending drain clips and half-cut locking features on source and gate clips, which are attached using solder, and a method of manufacturing that includes over-molding and partial exposure of terminals to enhance mechanical stability and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the package thickness is increased to prevent wire shorting, then wire shorting risk is reduced, but package cracking risk increases
Solution Approach 1:
The patent inverts the conventional package structure by exposing the drain terminal on the top surface instead of the bottom surface. This inversion allows for optimized wire routing and spacing that prevents wire shorting without requiring increased package thickness, thereby avoiding the cracking risk associated with thicker packages.
Solution Approach 2:
The patent utilizes the vertical dimension by implementing dual bending of the drain clips at approximately 90 degrees. This three-dimensional configuration allows wires to be routed in different spatial planes, preventing shorting while maintaining a thin package profile that reduces cracking susceptibility.
2Length of moving object
If the package is made thinner to reduce device size, then device thickness is reduced, but mechanical reliability deteriorates
Solution Approach 1:
By inverting the package structure to expose the drain terminal on the top surface, the patent enables a thinner overall package design while maintaining mechanical reliability through optimized internal wire routing and the dual bending configuration that provides structural reinforcement.
Solution Approach 2:
The patent employs a composite structure combining the leadframe, molding material, and solder joints in a integrated configuration. This composite design provides mechanical strength and reliability in a thin package, with the dual bending drain clips and half-cut locking features adding structural reinforcement without significant thickness increase.
3Reliability
If dual bending is applied to drain clips, then mechanical stability is improved, but manufacturing complexity increases
Solution Approach 1:
The dual bending of the drain clips is performed as a preliminary action during leadframe fabrication, before the semiconductor die is mounted and before final package assembly. This pre-forming of the 90-degree bends integrates the mechanical stability feature into the base structure without adding complex manufacturing steps later in the process.
Solution Approach 2:
The patent merges the dual bending feature with the half-cut locking features on the same drain clips. This combination integrates multiple functional benefits (mechanical stability from bending and attachment security from locking features) into a single manufactured component, reducing overall manufacturing complexity compared to implementing separate features.
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
The design improves mechanical robustness and thermal management by minimizing the risk of package cracking and detachment, while maintaining package reliability and facilitating efficient thermal dissipation through dual cooling systems.
Implementation Method 1
a die attached to the leadframe using a first solder, a source clip and a gate clip attached to the die using a second solder
Data Source
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AI summary
This disclosure relates to a semiconductor device comprising a leadframe, a die attached to the leadframe using a first solder, a source clip and a gate clip attached to the die using a second solder, and a drain clip attached to the leadframe. The semiconductor device is inverted, so that the source clip and the gate clip are positioned on the bottom side of the semiconductor device, wherein the leadframe is positioned on the top side of the semiconductor device so that the leadframe is a top exposed drain clip. The source clip and/or the drain clip comprise a half cut locking feature. The half cut locking feature can be formed as a wing and located at the sides of the source clip and the gate clip.