Clip-less Semiconductor Package with Recessed Leadframe
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Solution Overview
Problem
Conventional semiconductor packaging methods are complex and costly, requiring custom machinery and introducing significant electrical and thermal resistance, making them inefficient for scalable production and modification across different semiconductor die designs or multichip modules.
Innovation Solution
A clip-less packaged semiconductor device with a leadframe comprising a conductive sheet having a recessed region for the semiconductor die, where the leadframe is electrically coupled to the die and encapsulated, allowing for easy configuration and scalability without the need for custom bonding machinery or complex forming processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional leadframe packaging with wire bonding and post-encapsulation lead forming is used, then electrical connection is achieved, but device complexity and production cost increase due to custom trimming and forming machinery requirements
Solution Approach 1:
The patent extracts and eliminates the complex post-encapsulation lead forming and trimming steps from the packaging process. The leadframe is designed with leads that are pre-formed to their final configuration before encapsulation, removing the need for custom trimming and forming machinery and simplifying the overall packaging process while maintaining electrical connection reliability
Solution Approach 2:
The leadframe structure is prepared in advance with leads that are pre-formed and pre-positioned to their final desired configuration before the encapsulation process. This preliminary action eliminates the need for subsequent lead bending and shaping operations, reducing production complexity and machinery requirements
2Reliability
If quad-flat-no-lead approach with clips and wire bonding is used, then die attachment is achieved, but electrical resistance and inductance increase due to additional interfaces
Solution Approach 1:
The patent merges the die attachment function with the leadframe structure itself. The leadframe serves both as the mechanical support for die attachment and as the electrical interconnect, eliminating the need for separate clip components and wire bonds. This integration reduces the number of interfaces between components, thereby reducing electrical resistance and inductance while maintaining secure die attachment
3Shape
If custom trimming and forming machinery is used for leadframe processing, then lead configuration is achieved, but production time and cost increase
Solution Approach 1:
The leadframe is designed and manufactured with leads that are pre-formed to their final desired configuration during the leadframe fabrication process, before encapsulation. This preliminary formation of the lead shape eliminates the need for subsequent custom trimming and forming operations, significantly reducing production time and eliminating the requirement for specialized post-processing machinery
4Reliability
If multiple bonding and attachment steps are used, then die to leadframe connection is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent combines the die attachment and electrical connection functions into a single integrated process using the leadframe structure. The leadframe is designed with contact points that directly engage with the die electrodes, eliminating the need for separate wire bonding or ribbon bonding steps. This integration reduces the number of alignment operations required and lowers the cumulative precision requirements while ensuring reliable electrical connection
Data Source
AI summary
A clip-less packaged semiconductor device includes at least one semiconductor die having bottom and top surfaces each having at least one electrode. A leadframe comprising a sheet of conductive material having top and bottom surfaces, the top surface being substantially planar, the bottom surface having a recessed region having a thickness less than the thickness of the sheet of conductive material formed in the sheet and defining a plurality of planar lead contacts, is electrically coupled to the top surface of the die at its bottom surface in the recessed region. An encapsulating layer partially encloses the leadframe and die, wherein the encapsulating layer occupies portions of the recessed region not occupied by the die, wherein the bottom surface of the die and the plurality of leadframe contacts are exposed through the encapsulating layer at least at the bottom surface of the packaged semiconductor device.