Leadless IC Package Standoff Contacts Die Attach Pad
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Solution Overview
Problem
Conventional IC packages with external leads face challenges such as increased size, limited pin count, and electrical performance issues due to the horizontal extension of leads, which complicates PCB space utilization and requires additional inspection steps.
Innovation Solution
The development of leadless IC packages with standoff contacts and die attach pads, where electrical contacts and die attach pads are exposed below the molding layer, forming a direct thermal path and reducing physical and electrical interference, while allowing for various configurations to optimize space usage and connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external leads are used to form electrical connections, then electrical connectivity is achieved, but package size increases and PCB space is consumed
Solution Approach 1:
The patent extracts the harmful external leads from the package structure and replaces them with internal electrical contacts that are embedded within the molding compound. Only the essential electrical connection function is retained through contacts that extend vertically through the package, eliminating the horizontal extension that consumes PCB space.
Solution Approach 2:
The patent transitions from horizontal lead extension to vertical contact extension. Electrical contacts extend perpendicular to the package surface, utilizing the vertical dimension rather than horizontal space, thereby reducing the package footprint and PCB space requirements while maintaining electrical connectivity.
2Reliability
If external leads are arranged along the sides of IC packages, then electrical connections are formed, but pin count is limited by linear distance
Solution Approach 1:
The patent arranges electrical contacts in a grid pattern on the package surface, utilizing two-dimensional space rather than one-dimensional linear arrangement. This allows significantly higher pin counts by distributing contacts across the surface area rather than constraining them to the perimeter.
Solution Approach 2:
The patent segments the electrical connection function into multiple discrete contacts distributed across the package surface. This segmentation allows independent placement of numerous contacts in a compact arrangement, increasing pin count without requiring proportional increases in package dimensions.
3Reliability
If external leads are used, then electrical connections are established, but additional inspection steps are required for straightness and coplanarity
Solution Approach 1:
The patent removes the problematic external leads that require inspection for straightness and coplanarity. Electrical contacts are embedded within the molding compound, which naturally provides mechanical support and alignment, eliminating the need for separate inspection steps for lead geometry.
Solution Approach 2:
The patent merges the electrical contact function with the structural support function by embedding contacts within the molding compound. The molding material simultaneously provides mechanical support, electrical insulation, and alignment for the contacts, eliminating the need for separate inspection of coplanarity and straightness.
4Reliability
If leads extend from bonding fingers to external portions, then electrical connectivity is achieved, but total electrical signal length increases affecting performance
Solution Approach 1:
The patent extracts the excessive lead length from the electrical signal path by eliminating external leads. Electrical contacts provide direct vertical pathways from the bonding fingers through the molding compound to the package surface, significantly reducing the total electrical signal length and improving high-frequency performance.
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 solution reduces the size of IC packages, eliminates the need for lead bending, enhances thermal dissipation, and improves electrical performance by enabling higher pin density and reduced interference with PCB components, while allowing for efficient surface mounting and heat management.
Implementation Method 1
The copper layer may act as a heat sink to dissipate heat generated by the IC chip during normal operation
Data Source
AI summary
A leadless integrated circuit (IC) package comprising an IC chip mounted on a die attach pad and a plurality of electrical contacts electrically connected to the IC chip. The IC chip, the electrical contacts, and the die attach pad are all covered with a molding material, with portions of the electrical contacts and die attach pad protruding from a bottom surface of the molding material.