Wiring Substrate With Magnetic Layer Openings for Signal Integrity
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Solution Overview
Problem
There is a demand for a wiring substrate that minimizes adverse effects on signal properties, particularly in reducing insertion loss and improving signal transmission performance, which existing technologies have not adequately addressed.
Innovation Solution
The wiring substrate incorporates a magnetic layer with openings extending through its thickness, separating it from the signal wiring structure, and includes a coil wiring and insulation layers to enhance signal transmission without direct contact with the magnetic layer, using materials like manganese-Zn ferrite and Cu alloys for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the magnetic layer is placed close to the coil wiring to enhance inductance, then the coil performance is improved, but the magnetic layer interferes with signal transmission causing increased insertion loss
Solution Approach 1:
The magnetic layer is segmented by forming openings (through-holes) through its thickness, dividing it into multiple magnetic regions. This segmentation allows the signal wiring to pass through the openings without direct contact with the magnetic material, reducing magnetic interference and insertion loss while maintaining sufficient magnetic field coupling for coil inductance.
Solution Approach 2:
The openings in the magnetic layer act as intermediaries, allowing the signal wiring structure to traverse the magnetic layer region without direct contact. This intermediary structure enables the signal path to bypass the harmful magnetic field while still benefiting from the magnetic shielding and inductance enhancement where needed.
2Object-affected harmful factors
If the magnetic layer covers the entire lower surface including signal wiring areas, then magnetic shielding is improved, but signal transmission performance deteriorates due to magnetic interference
Solution Approach 1:
The magnetic layer is segmented into regions: areas with magnetic material for shielding and signal areas with openings for transmission. This selective segmentation maintains magnetic shielding where needed while creating clear signal paths where required, resolving the contradiction between shielding and signal integrity.
Solution Approach 2:
The magnetic layer exhibits local quality variations - having magnetic material in some regions (for shielding and inductance) and openings in other regions (for signal transmission). This local differentiation allows simultaneous achievement of magnetic shielding and high-quality signal transmission in different areas of the same structure.
3Loss of energy
If the magnetic layer is removed from under the signal wiring to improve signal transmission, then insertion loss is reduced, but magnetic shielding and coil performance are compromised
Solution Approach 1:
Rather than completely removing the magnetic layer, it is segmented with openings only in the signal transmission areas. This partial removal approach maintains magnetic shielding in non-signal areas while eliminating interference in signal areas, achieving both goals simultaneously.
Solution Approach 2:
The solution moves from a two-dimensional planar magnetic layer to a three-dimensional structure with vertical openings. This dimensional change allows the magnetic layer to provide shielding in the horizontal plane while allowing signal transmission through the vertical dimension via the openings.
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 configuration reduces insertion loss and enhances signal transmission performance by isolating the magnetic layer from the signal wiring, resulting in improved high-frequency signal transmission and a more efficient use of space with the magnetic coil.
Implementation Method 1
a magnetic layer covering the lower surface of the insulation layer and the coil wiring
Implementation Method 2
The magnetic layer includes an opening extending through in a thickness-wise direction
Implementation Method 3
a first insulation layer covering the coil wiring, an upper surface of the magnetic layer, and a wall surface of the opening
Implementation Method 4
The signal wiring structure that transmits a signal of a semiconductor element in the wiring substrate when the semiconductor element is mounted on the wiring substrate
Data Source
AI summary
A wiring substrate includes a coil wiring and a magnetic layer that is in contact with a lower surface of the coil wiring and includes an opening extending through in a thickness-wise direction. The wiring substrate further includes a first insulation layer covering the coil wiring, an upper surface of the magnetic layer, and a wall surface of the opening and a signal wiring structure formed so that a signal of a semiconductor element, when mounted on the wiring substrate, travels through the opening of the magnetic layer. The signal wiring structure includes a first wiring portion located on an upper surface of the first insulation layer and a first via wiring located inward from the opening of the magnetic layer and connected to the first wiring portion. The magnetic layer is not in contact with the signal wiring structure.