Packaged IC Mitigating Parasitic Coupling via Ground Shield Wire
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing integrated circuit packaging technologies face challenges with parasitic interference and limited frequency range due to close proximity of wirebonds, which degrades signal quality and restricts high-frequency operations.
Innovation Solution
A packaged integrated circuit design featuring a die paddle and ground lead with dual conductive paths, including a via and wirebonds, to reduce parasitic coupling and improve signal integrity, allowing for extended frequency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wirebonds are used to electrically connect the die to the leads in close proximity within the package, then electrical connection is achieved, but parasitic coupling degrades the signal quality
Solution Approach 1:
The patent introduces a ground shield wire as an intermediary element positioned between the signal wire and other conductors. This ground shield acts as a mediator that blocks parasitic electromagnetic coupling while maintaining necessary electrical connections, thereby improving signal quality without requiring increased spacing between components.
Solution Approach 2:
The patent extracts the ground function from the existing leadframe structure and creates a dedicated ground shield wire that is specifically positioned to counteract parasitic coupling. By separating the grounding function into a distinct element, the patent effectively removes the harmful parasitic effects while preserving the compact package design.
2Adaptability or versatility
If wirebonds are placed in close proximity to achieve compact packaging, then device miniaturization is achieved, but the frequency range is limited due to parasitic interference
Solution Approach 1:
The ground shield wire serves as an intermediary that enables compact packaging while protecting against parasitic coupling. It allows the package to maintain small volume with closely spaced wirebonds while the ground shield blocks electromagnetic interference, thereby extending the usable frequency range despite the compact dimensions.
Solution Approach 2:
The patent applies local quality by positioning the ground shield wire specifically in regions where parasitic coupling occurs most severely. Rather than uniformly increasing spacing throughout the package, the ground shield provides localized protection in critical areas, maintaining compact overall volume while enabling high-frequency operation in specific signal paths.
3Reliability
If multiple wirebonds are used to connect the die to the leads, then electrical connectivity is improved, but parasitic interference increases
Solution Approach 1:
The patent merges the grounding function with the wirebond structure by implementing ground shield wires that are bonded to the die and leadframe together with the signal wires. This combining of multiple functions (signal transmission and shielding) into a single integrated wirebond structure improves electrical connectivity while the ground portion simultaneously suppresses parasitic interference.
Solution Approach 2:
The ground shield wire acts as an intermediary element that is electrically connected to both the die and the leadframe ground. This intermediary connection provides a low-impedance ground path that actively counteracts parasitic interference generated by multiple wirebonds, thereby maintaining reliable electrical connectivity without the harmful effects of parasitic coupling.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A packaged IC has a package with a die paddle, a signal lead, and a ground lead. The packaged IC also has a die, secured to the package, with a ground pad and a signal pad. The signal pad is electrically connected to the signal lead, and the ground pad is electrically connected to both the die paddle and the ground lead.