Stacked Coil Substrate for Inductance in Miniaturized Planar Footprint
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Solution Overview
Problem
The miniaturization of inductors using winding coils is limited by the planar size and thickness, which restricts the increase in inductance due to a reduced volume ratio of the winding.
Innovation Solution
A coil substrate is designed with multiple structural bodies stacked via adhesion layers, each containing a spiral coil wiring pattern, allowing series connection to form a spiral coil with increased windings without altering the planar shape, using insulating layers and via-wirings to enhance inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inductor is miniaturized below 1.6mm×1.6mm planar size, then the device size is reduced, but the inductance cannot be increased due to reduced winding volume ratio
Solution Approach 1:
The patent transitions from a planar two-dimensional winding structure to a three-dimensional stacked structure. Multiple coil structures are stacked in the vertical direction (thickness direction) and connected via conductive via holes, enabling the coil to extend into the third dimension. This dimensional change allows increased inductance within a reduced planar footprint by utilizing vertical space for additional windings.
Solution Approach 2:
The patent implements a nested structure where multiple coil windings are stacked one above another in the vertical direction, with each coil layer nested within the overall inductor package. The via holes connect these nested layers, creating a compact multi-turn coil structure that achieves high inductance in a small volume by nesting multiple winding turns within the same planar projection area.
2Reliability
If the winding thickness is increased to maintain inductance, then the inductance is preserved, but the planar shape size cannot be reduced below 1.6mm×1.6mm
Solution Approach 1:
Instead of increasing winding thickness in the planar direction, the patent distributes multiple winding turns across multiple stacked layers in the vertical dimension. This approach maintains the required inductance by increasing the number of effective turns through vertical stacking, while keeping each individual layer thin and allowing the overall structure to fit within a compact planar footprint.
Solution Approach 2:
The patent segments the continuous winding structure into multiple discrete coil layers stacked in the vertical direction. Each layer contains a portion of the total windings, and the segments are electrically connected through via holes. This segmentation allows the winding to be distributed across multiple thin layers rather than concentrated in a single thick layer, enabling miniaturization while maintaining inductance.
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 approach enables miniaturization of the coil substrate while increasing inductance, allowing for more compact electronic devices without compromising performance.
Implementation Method 1
the plurality of structural bodies are stacked via an adhesion layer
Data Source
AI summary
A coil substrate includes a plurality of structural bodies, each of which comprises a first insulating layer, a wiring formed on the first insulating layer and configured to serve as a part of a spiral coil, and a second insulating layer formed on the first insulating layer and configured to cover the wiring. The plurality of structural bodies are stacked via an adhesion layer. The spiral coil is formed by series-connecting the wirings of adjacent ones of the plurality of structural bodies.