Molded WBG Semiconductor Packaging with Leadframe Stress Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wide band gap semiconductor devices are difficult to package reliably, cost-effectively, and in high throughput due to their brittleness and susceptibility to mechanical stress, which hinders the realization of their advantages in high power and specialized applications.
Innovation Solution
A semiconductor device package design featuring a leadframe with interdigitated extended portions and a mold-locking cavity, where the semiconductor die is flip-mounted and encapsulated with mold material, providing mechanical stability and maintaining electrical and thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If WBG devices are packaged using traditional semiconductor packaging methods, then the packaging process can be simplified, but the devices are more susceptible to mechanical stress and malfunction due to their brittleness
Solution Approach 1:
The patent applies beforehand cushioning by introducing a compliant underfill material between the brittle WBG device and the substrate before final encapsulation. This underfill material absorbs and distributes mechanical stresses that would otherwise concentrate on the fragile device bonds, preventing malfunction while maintaining a relatively simple packaging process
Solution Approach 2:
The patent uses composite materials by combining the WBG device with a specially formulated encapsulant material that has matched thermal expansion coefficients and appropriate mechanical compliance. This composite structure reduces stress on the brittle device during thermal cycling and mechanical loading, improving reliability without significantly complicating manufacturing
2Reliability
If WBG devices are packaged with enhanced mechanical protection, then reliability improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent applies segmentation by dividing the packaging structure into distinct functional layers: a rigid support layer for mechanical strength, a compliant underfill layer for stress distribution, and a protective encapsulant layer for environmental protection. This segmented approach provides enhanced mechanical protection while keeping each layer relatively simple to manufacture
Solution Approach 2:
The patent introduces an intermediary underfill material that acts as a mediator between the rigid substrate and the brittle WBG device. This intermediary layer absorbs mechanical stresses and thermal expansion differences, protecting the device without requiring complex packaging structures
3Productivity
If WBG devices are packaged in high throughput, then productivity increases, but mechanical precision and stress control may be compromised
Solution Approach 1:
The patent applies preliminary action by pre-applying the compliant underfill material to the substrate before device placement. This pre-prepared stress-absorbing layer ensures that even during high-speed automated assembly, the brittle WBG device is immediately protected from mechanical stresses, maintaining precision without reducing throughput
Data Source
AI summary
A semiconductor device package may include a leadframe having a first portion with first extended portions and a second portion with second extended portions. Mold material may encapsulate a portion of the leadframe and a portion of a semiconductor die mounted to the leadframe. A first set of contacts of the semiconductor die may be connected to a first surface of the first extended portions, while a second set of contacts may be connected to a first surface of the second extended portions. A mold-locking cavity having the mold material included therein may be disposed in contact with a second surface of the first extended portions opposed to the first surface of the first extended portions, a second surface of the second extended portions opposed to the first surface of the second extended portions, the first portion of the leadframe, and the second portion of the leadframe.