Molded RF Power Package Leads With Stress-Relief Bending Zones
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Solution Overview
Problem
Molded RF power packages with bent leads suffer from reliability issues due to delamination of the molding compound, which is exacerbated by the rigidity required for proper sealing during the molding process, leading to potential torsion and contamination of the wire bonding area.
Innovation Solution
Incorporating a weakening structure, such as recesses or holes, in the curved sub-segment of the leads allows for bending without excessive delamination forces, while maintaining sufficient stiffness to prevent torsion and ensure reliable sealing and wire bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the leads are made rigid to ensure proper sealing during molding, then sealing reliability is improved, but delamination of the molding compound occurs due to excessive forces during bending
Solution Approach 1:
The lead is designed with non-uniform cross-sectional properties: the first segment (inside molding compound) maintains full thickness for strong adhesion and sealing, while the second segment (outside molding compound) includes a reduced-thickness portion that acts as a stress relief zone. This local variation in structural quality allows the lead to be rigid where needed for sealing while being flexible where needed for bending without delamination.
2Adaptability or versatility
If the leads are bent to achieve desired package configuration, then adaptability is improved, but torsion and contamination of the wire bonding area occur
Solution Approach 1:
The lead is divided into functionally distinct segments: the first segment remains straight and rigid for reliable bonding and sealing, while the second segment contains the bending portion with reduced thickness. This segmentation isolates the bending deformation to a specific zone, preventing torsion from propagating to the wire bonding area and preventing contamination of sensitive regions.
3Ease of operation
If the lead cross-section is reduced in the second segment, then ease of bending is improved, but mechanical strength decreases
Solution Approach 1:
The lead employs localized thinning only in the second segment where bending is required, while the first segment maintains full cross-sectional thickness for structural integrity. This creates a gradient of mechanical properties optimized for each functional requirement: flexibility where bending is needed, and strength where load-bearing is critical.
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 weakening structure enhances the reliability of the molded RF power package by reducing delamination and torsion, ensuring effective sealing and maintaining the integrity of the wire bonding area, thus improving the overall performance and reliability of the package.
Implementation Method 1
a body of solidified molding compound that fixedly connects the heat-conducting substrate to the plurality of leads by directly adhering to the plurality of leads and heat-conducting substrate
Implementation Method 2
a heat-conducting substrate having a first surface, corresponding to the top surface in FIG. 1, and an opposing second surface. Heat-conducting substrate 30 is typically made from copper or a copper alloy
Data Source
AI summary
The present disclosure relates to a molded radiofrequency, ‘RF’, power package. The present disclosure further relates to a method for manufacturing such package.According to example embodiments, weakening structures are provided in the leads to allow the leads to be bent without causing delamination in the body of solidified molding compound.