Cap Layer Ground Plane for Overhang Die Packaging
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Solution Overview
Problem
The overhang die configuration in semiconductor packaging limits device density and complicates signal connections due to the difficulty in connecting the semiconductor die to the ground pad, which hinders the reduction of package footprint and increase in packaging density.
Innovation Solution
A cap layer is formed on top of the semiconductor die to act as a ground or power plane, with a cap bonding wire connecting the die to the cap layer, facilitating easier connections and maximizing die size without sacrificing the overhang configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If an overhang die configuration is used to maximize die size and reduce package footprint, then the packaging density is improved, but the difficulty of connecting the semiconductor die to the ground pad increases
Solution Approach 1:
A cap layer is introduced as an intermediary component between the semiconductor die and the ground pad. This cap layer serves as a mediator that facilitates electrical connection while allowing the die to maintain its overhang configuration. The cap layer is connected to the ground pad through conventional means and provides a surface for wire bonding to the die, thus resolving the connection difficulty without compromising the compact package design.
2Productivity
If the semiconductor die is positioned to overhang the leads, then the packaging density is increased, but the complexity of the wire bonding process increases
Solution Approach 1:
The cap layer acts as an intermediary platform that simplifies the wire bonding process. Instead of attempting to bond wires directly to the overhanging die which creates complex routing challenges, the wire bonding is performed on the cap layer which provides a stable, accessible surface. This intermediary structure maintains the high packaging density achieved through the overhang configuration while significantly reducing the complexity of the wire bonding operation.
3Device complexity
If the die pad is used as the ground plane in a typical leadframe configuration, then the structure is simplified, but the packaging density is limited due to wasted space
Solution Approach 1:
The invention transitions from a two-dimensional planar ground plane (the die pad) to a three-dimensional cap layer structure positioned above the die. This dimensional change allows the ground plane function to be separated from the mechanical support function, enabling the die to overhang the leads and maximize space utilization. The cap layer provides the ground plane functionality in a location that does not constrain the die positioning, thus achieving both structural simplicity and high packaging density.
Data Source
AI summary
A method of manufacture of an integrated circuit packaging system includes: attaching a semiconductor die to a die pad of a leadframe; forming a cap layer on top of the semiconductor die for acting as a ground plane or a power plane; and connecting the semiconductor die to the cap layer through a cap bonding wire.