Leadframe Topset Feature for Chip Scale Package Die Size
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Solution Overview
Problem
Conventional semiconductor packages face challenges in miniaturization and die size optimization for use in low-power and ultra-portable electronic devices, where they need to balance electrical and mechanical connectivity with protection from environmental hazards while maintaining a small footprint.
Innovation Solution
The development of chip scale semiconductor packages featuring a leadframe with a topset feature and interconnect structure that supports a discrete device, allowing for maximum die size utilization and connectivity, using a conductive path for heat dissipation and encapsulation to protect the die, while maintaining a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional semiconductor packages are miniaturized, then the package size is reduced, but the die size is limited and thermal dissipation becomes insufficient
Solution Approach 1:
The patent introduces a topset feature that extends vertically from the leadframe, creating a third-dimensional connection path. This allows the die to be positioned higher above the leadframe plane, enabling larger die sizes to be accommodated within a compact package footprint by utilizing vertical space rather than horizontal space only.
Solution Approach 2:
The topset feature serves multiple functions simultaneously: it provides mechanical support for the die, establishes electrical connections between the die and leadframe, and facilitates thermal dissipation pathways. This multi-functionality allows the package to maintain small size while accommodating larger dies that require robust support and connectivity.
2Reliability
If bond wires are used to connect the IC die to terminals, then electrical connection is achieved, but the package becomes more complex and vulnerable to mechanical shock
Solution Approach 1:
The patent eliminates the bond wire interconnect layer from the package structure by establishing direct electrical connections between the die and leadframe through the topset feature. This extraction of the bond wire function simplifies the package structure, reduces the number of components, and eliminates the vulnerability of thin bond wires to mechanical shock and fatigue.
Solution Approach 2:
The topset feature merges the mechanical support function and electrical connection function into a single integrated structure. Instead of having separate bond wires for electrical connection and separate support structures, the topset feature combines both functions, reducing overall package complexity and improving reliability.
3Object-affected harmful factors
If the die is fully encapsulated to protect from environmental hazards, then protection is improved, but thermal dissipation becomes more difficult
Solution Approach 1:
The patent applies selective encapsulation where the encapsulating material covers the die and leadframe but intentionally leaves the topset feature and its connection points exposed. This local quality approach provides environmental protection where needed while maintaining open pathways for thermal dissipation through the topset feature, allowing heat to escape from the die without being trapped by complete encapsulation.
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 enables the creation of semiconductor packages that are more robust, thermally efficient, and have a smaller footprint compared to conventional designs, suitable for low-power and ultra-portable devices, with improved mechanical and electrical connectivity, and reduced wirebonding requirements.
Implementation Method 1
conductive path for heat dissipation
Data Source
AI summary
Chip scale semiconductor packages and methods for making and using the same are described. The chip scale semiconductor packages comprise a leadframe supporting a die that contains a discrete device. The chip scale semiconductor device also contains and an interconnect structure that also serves as a land for the package. The leadframe contains a topset feature adjacent a die attach pad supporting the die, a configuration which provides a connection to the interconnect structure as well as the backside of the die. This leadframe configuration provides a maximum die size to be used in the chip scale semiconductor packages while allowing them to be used in low power and ultra-portable electronic devices. Other embodiments are described.