Thin-Film Power Inductor Stacking for Uniform Miniaturization
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Solution Overview
Problem
Traditional methods for manufacturing high-power and high-current inductors face challenges in miniaturization due to uneven thickness caused by direct stacking of planar magnetic sheets and the need for increased silver layer thickness, which limits the development of miniaturized electronics.
Innovation Solution
A manufacturing method for thin-film power inductors involving the formation of alloy magnetic sheets, hole-shaped magnetic sheets, and a coil layer, where the sheets are aligned and stacked with electrodes, followed by secondary pressing and electroplating to create uniform thin-film inductors with outer electrodes, enabling efficient miniaturization and large-scale production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If traditional winding and integral molding process are used, then high-power and high-current inductors can be manufactured, but miniaturization and integration requirements cannot be met
Solution Approach 1:
The inductor is segmented into multiple thin magnetic sheets (each 5-50 μm thick) stacked in sequence, with coil layers inserted between them. This segmentation enables miniaturization while maintaining power handling capability through the distributed magnetic path and reduced eddy current losses in thin sheets.
Solution Approach 2:
The patent transitions from traditional 3D winding structures to a planar thin-film stacking approach, utilizing the thickness dimension (z-axis) for magnetic sheet stacking while keeping the planar footprint minimal. This dimensional transformation enables high power density in a compact form factor suitable for integrated electronics.
2Power
If silver paste filling in printing groove is adopted to increase silver layer thickness for high current, then current carrying capacity is improved, but miniaturization development is limited
Solution Approach 1:
The silver paste is distributed across multiple thin magnetic sheets rather than concentrated in a single thick layer. Each sheet contains a thin silver layer with electrodes that connect through the stack, providing cumulative current carrying capacity without increasing the thickness of individual layers, thus enabling miniaturization.
Solution Approach 2:
The patent uses composite construction with multiple magnetic sheets, silver paste layers, and insulating materials stacked together. This composite structure achieves high current capacity through the cumulative effect of multiple thin conductive paths while maintaining overall compact dimensions.
3Ease of manufacture
If planar magnetic sheets are directly stacked on coil layer, then manufacturing is simplified, but thickness uniformity deteriorates due to open space between electrodes
Solution Approach 1:
Holes are pre-formed in the magnetic sheets at positions corresponding to the coil electrodes before stacking. This preliminary action ensures that when sheets are stacked, the holes align with electrodes, eliminating gaps and ensuring uniform thickness distribution throughout the assembly, while maintaining simple stacking manufacturing.
4Loss of energy
If alloy magnetic materials with low loss are used, then conversion efficiency is improved, but cost and miniaturization requirements create conflicts
Solution Approach 1:
The patent changes the physical parameters of the magnetic material by reducing sheet thickness to 5-50 μm range, which fundamentally alters the eddy current characteristics. This parameter change enables the use of alloy magnetic materials with low inherent loss while achieving minimal overall thickness, resolving the conflict between low loss performance and miniaturization.
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
The method allows for the production of small, uniform thin-film inductors with consistent performance, addressing the limitations of traditional methods by enabling miniaturization and high-efficiency manufacturing.
Implementation Method 1
Alloy powder is evenly mixed with plasticizer, adhesive, curing agent, dispersing agent and organic solvent to form slurry
Implementation Method 2
the slurry is evenly applied on a polyethylene terephthalate (PET) film, and drying is performed to form a magnetic band
Implementation Method 3
A hole is opened on each of a part of the plurality of magnetic sheets to form one of hole-shaped magnetic sheets
Implementation Method 4
Electrodes are processed on an insulating substrate to form a coil layer
Implementation Method 5
One of the plurality of magnetic sheets, one of the hole-shaped magnetic sheets, the coil layer, another one of the hole-shaped magnetic sheets and another one of the plurality of the magnetic sheets are sequentially stacked and pressed to form a block
Implementation Method 6
The block is secondarily pressed, and a secondarily pressed block is cut to form an individual product
Implementation Method 7
A cut individual product formed by cutting is baked to form a main body
Implementation Method 8
Silver paste is applied on two ends of the main body to form outer electrodes respectively such that the outer electrodes are electrically connected to the electrodes respectively
Implementation Method 9
A nickel layer and a tin layer are electroplated on a surface of each of the outer electrodes to form a thin-film power inductor
Data Source
AI summary
A manufacturing method of a thin-film power inductor includes: Alloy powder is mixed with plasticizer, adhesive, curing agent, dispersing agent and organic solvent to form slurry; the slurry is applied on a PET film, and drying to form a magnetic band; and the magnetic band is cut to form a plurality of magnetic sheets. A hole is opened on a magnetic sheet to form a hole-shaped magnetic sheet. Electrodes are processed on an insulating substrate to form a coil layer. Magnetic sheets, hole-shaped magnetic sheets, and the coil layer are stacked to form a block. The block is pressed, and the block is cut to form an individual product. The individual product is baked to form a main body. Silver paste is applied on the main body to form outer electrodes. A nickel layer and a tin layer are electroplated on outer electrodes to form a thin-film power inductor.