Dummy Conductor Shape for High-Frequency Eddy Current Suppression
Solution Overview
Problem
High-frequency currents flowing through wiring in semiconductor devices generate eddy currents in nearby dummy conductor patterns, leading to instability in transmission characteristics, particularly at frequencies of 5 GHz or higher.
Innovation Solution
The semiconductor device incorporates dummy conductor patterns with internal angles greater than 180° and polygonal shapes with dents, increasing the complexity of their outer shape, which inhibits the flow of eddy currents due to the skin effect, thereby reducing the fluctuation of circuit constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rectangular dummy conductor patterns are formed near the wiring to facilitate production processing, then the ease of manufacture is improved, but eddy currents are generated in the dummy conductor patterns when high-frequency current flows through the wiring, causing fluctuation in circuit constants and deterioration of transmission characteristics
Solution Approach 1:
The patent applies asymmetry by changing the dummy conductor pattern shape from a simple rectangle to a complex polygonal shape with at least one internal angle greater than 180 degrees (a reentrant corner). This asymmetric geometric feature creates regions where eddy currents are suppressed, thereby reducing the harmful electromagnetic effects while maintaining the manufacturing facilitation function
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the dummy conductor pattern - specifically introducing internal angles greater than 180 degrees and creating dent structures. These parameter changes alter the electromagnetic field distribution and suppress eddy current generation, resolving the contradiction between ease of manufacture and transmission characteristic stability
2Device complexity
If simple rectangular dummy conductor patterns are used, then the device complexity is reduced, but the eddy current magnitude increases causing larger fluctuation in circuit constants
Solution Approach 1:
The patent introduces geometric asymmetry through reentrant corners (internal angles > 180°) in the dummy conductor pattern. This asymmetric shape configuration disrupts the continuous eddy current paths that would otherwise form in simple rectangular patterns, thereby reducing eddy current magnitude with minimal increase in overall device complexity
Solution Approach 2:
The patent creates a form of geometric 'porosity' by introducing dent structures and reentrant corners that create discontinuities in the conductor pattern. These features effectively break up eddy current paths similar to how porous structures disrupt fluid flow, reducing the magnitude of harmful eddy currents while maintaining structural integrity
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 design effectively suppresses eddy currents, enhancing the stability of transmission characteristics and maintaining a small level of circuit constant fluctuation, even at high frequencies.
Implementation Method 1
due to a skin effect, a current density thereof is increased as the current density comes closer to a surface of a conductor. Accordingly, the complexity of an outer shape of the first dummy conductor pattern effectively inhibits a flow of the eddy current in the pattern
Implementation Method 2
by a magnetic field generated by the wiring 101, an eddy current is generated in each of the dummy conductor patterns 102 positioned near the wiring 101
Implementation Method 3
When the eddy current is generated as described above, according to Lentz's law, a magnetic field in a direction in which the magnetic field generated by the wiring 101 is offset is generated
Data Source
AI summary
A semiconductor device (1) includes a wiring (10) and dummy conductor patterns (20). The wiring (10) is a wiring through which a current with a frequency of 5 GHz or higher flows. Near the wiring (10), the dummy conductor patterns (20) are formed. A planar shape of each of the dummy conductor patterns (20) is equivalent to a shape with an internal angle larger than 180°.