Flat No-Lead Package Wettable Sidewall Lead Coupling
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Solution Overview
Problem
Existing flat no-lead semiconductor packages face challenges in providing reliable surface-mounted structures with exposed leads for efficient electrical connections, as they often rely on flat surfaces which may not offer sufficient contact area or reliability for coupling with other components.
Innovation Solution
The introduction of a surface mounted structure with recessed members on the end portions, allowing for a wettable sidewall for coupling with exposed leads, enhances the coupling medium's reception and provides additional connection points between the semiconductor die and the leadframe, utilizing a coupling medium like solder paste or adhesive for secure attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flat surface is used for coupling the surface mounted structure to the leadframe, then the structure is simple to manufacture, but the contact area and coupling reliability are insufficient
Solution Approach 1:
The end portions of the surface mounted structure are extended beyond the plane of the body, creating a three-dimensional configuration that provides additional contact area with the leadframe. This dimensional extension transforms a potentially two-dimensional coupling interface into a multi-dimensional one, improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The surface mounted structure is divided into a body and multiple end portions that can be independently configured. Each end portion can be tailored to specific coupling requirements, allowing optimization of the coupling interface while keeping the overall structure manageable and manufacturable.
2Reliability
If recessed members are added to the end portions for receiving coupling medium, then the wettable sidewall area increases for better coupling, but the manufacturing complexity increases
Solution Approach 1:
The end portions are designed with modified geometric parameters compared to the body, specifically extending beyond the body plane and incorporating recessed members. These parameter changes create wettable sidewalls that improve attachment reliability while maintaining compatibility with standard manufacturing processes through controlled variations in shape and dimension.
Solution Approach 2:
The recessed members are localized features positioned specifically at the end portions where coupling with the leadframe occurs. This local modification concentrates the enhanced coupling functionality where it is most needed, without requiring complex changes to the entire structure, thus balancing manufacturing ease with attachment reliability.
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 improves the reliability and versatility of electrical connections by providing a secure and robust attachment method, enabling more reliable soldering to PCBs and other components, and allowing for various interconnection possibilities beyond traditional flat surfaces.
Implementation Method 1
an end portion of the surface mounted structure also includes a wettable side wall for the coupling to the exposed lead
Data Source
AI summary
The present disclosure is directed to a flat no-lead semiconductor package with a surfaced mounted structure. An end portion of the surface mounted structure includes a recessed member so that the surface mounted structure is coupled to leads of the flat no-lead semiconductor package through, among others, the sidewalls of the recessed members.