IC Package Isolated Lead Fingers for High Density
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Solution Overview
Problem
Current integrated circuit packaging technologies face challenges in reducing package size, increasing lead count, improving reliability, and controlling manufacturing costs, particularly due to the complexity and cost associated with lead frame packaging and the limitations of laminate substrates in withstanding pressure cooker tests and corrosion.
Innovation Solution
The solution involves forming fingers and a die pad, applying a fill material around them, creating a cavity, and attaching an integrated circuit die over the die pad with the fill material, which enhances lead count, process flow, and reliability while reducing manufacturing costs by simplifying the fabrication process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lead frame packaging is used to increase lead count, then the number of connections is improved, but manufacturing complexity and cost increase due to multiple fabrication steps
Solution Approach 1:
The lead frame is divided into separate fingers that are formed and processed independently, then assembled together. This segmentation allows each finger to be manufactured using simpler processes while achieving high lead count through the multi-finger configuration.
Solution Approach 2:
The invention transitions from planar lead arrangement to a three-dimensional finger structure with multiple levels and orientations. This dimensional change enables significantly higher lead count within the same package footprint without proportionally increasing process complexity.
2Quantity of substance
If lead width is reduced to increase lead count, then the number of connections is improved, but reliability deteriorates due to bending and open/short circuits
Solution Approach 1:
The lead structure is segmented into multiple thick-finger elements rather than using thin leads. Each finger maintains sufficient width and thickness for mechanical strength while the segmented configuration achieves high lead count through parallel arrangement of multiple fingers.
Solution Approach 2:
The lead frame uses composite construction with copper fingers providing electrical conductivity and mechanical strength, combined with supportive structures that prevent bending and deformation, thereby maintaining reliability while achieving high lead density.
3Quantity of substance
If laminate substrate is used to increase lead count, then the number of connections is improved, but reliability deteriorates due to inability to withstand pressure cooker tests and corrosion
Solution Approach 1:
The invention uses a disposable lead frame structure that provides the necessary electrical connections for the device lifecycle. The lead frame is designed as a single-use component that is discarded with the device, eliminating the need for durable, reusable substrate materials that would require complex corrosion-resistant designs.
Solution Approach 2:
The invention extracts the lead connections from the substrate and places them on the device surface as separate finger elements. This extraction allows the use of simple, reliable lead frame materials without requiring the substrate to provide both mechanical support and corrosion resistance, thereby improving overall reliability.
4Quantity of substance
If additional components such as metal film, electrodes, column-like structures, and pattern layers are added to increase lead count, then the number of connections is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The invention merges multiple functions into the single lead frame structure. The fingers serve as both the electrical connections and the mechanical support, eliminating the need for separate metal films, electrodes, and column-like structures that would otherwise be required to achieve the same lead count.
Solution Approach 2:
The lead frame fingers are designed as universal components that simultaneously provide electrical connectivity, mechanical support, and structural definition. This multi-functionality eliminates the need for multiple specialized components, thereby reducing manufacturing complexity while maintaining high lead count.
Data Source
AI summary
An integrated circuit package system comprising: forming a finger; forming a die pad adjacent the finger; applying a fill material around the finger and the die pad; forming a cavity in the finger and fill material; and attaching an integrated circuit die over the die pad adjacent the finger with the fill material.