Photosensitive Insulating Paste for Crack-Resistant Inductor Layers
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Solution Overview
Problem
Photosensitive insulating pastes used in inductor components face issues with high dielectric constant and large coefficient of linear expansion differences between insulating layers and coil wires, leading to defects like cracks and limited coil wire density.
Innovation Solution
A photosensitive insulating paste composition including glass frit, silicon oxide filler, and optional alumina or titania fillers, optimized within specific volume ranges to balance resolution, dielectric constant, and coefficient of linear expansion, enhancing adhesion and reducing stress-induced cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photosensitive insulating paste contains high glass frit content (50-90% by mass) as in prior art, then resolution is increased, but the coefficient of linear expansion difference between insulating layers and coil wires becomes large, causing cracks
Solution Approach 1:
The patent changes the chemical composition parameters of the glass frit, specifically incorporating SiO2 (40-70 wt%), B2O3 (20-40 wt%), and Al2O3 (5-20 wt%) within controlled ranges. This parameter optimization adjusts the coefficient of linear expansion to match coil wires while maintaining resolution, preventing cracks without sacrificing manufacturing precision.
2Manufacturing precision
If photosensitive insulating paste uses high glass frit content (50-90% by mass), then resolution is improved, but dielectric constant becomes high, requiring increased insulating layer thickness
Solution Approach 1:
The patent optimizes the glass frit composition with specific ratios of SiO2, B2O3, and Al2O3, and controls the particle size distribution (D50: 0.5-5 μm, D90: 5-15 μm). These parameter changes reduce the dielectric constant while maintaining high resolution, allowing thinner insulating layers and enabling increased coil wire density.
3Reliability
If insulating layer thickness is increased to compensate for high dielectric constant, then dielectric performance is maintained, but the number of coil wires that can be accommodated decreases
Solution Approach 1:
By changing the dielectric constant through optimized glass frit composition (SiO2 40-70 wt%, B2O3 20-40 wt%, Al2O3 5-20 wt%), the patent reduces the required insulating layer thickness. This parameter change enables higher coil wire density while maintaining adequate dielectric performance and reliability.
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 optimized paste composition improves the reliability and inductance value of inductor components by reducing crack formation and increasing coil wire density, while maintaining a moderate dielectric constant and coefficient of linear expansion.
Implementation Method 1
a photopolymerization initiator
Implementation Method 2
a softening point of the glass frit is 700° C. or above and below 900° C.
Implementation Method 3
The first inorganic filler is a silicon oxide having crystallinity
Data Source
AI summary
A photosensitive insulating paste contains glass frit, a first inorganic filler, a second inorganic filler, an alkali-soluble polymer, a photosensitive monomer, a photopolymerization initiator, and a solvent. The glass frit contains SiO2 and B2O3 as a base component and contains at least one of the aluminum element, sodium element, or phosphorus element as a minor component. The first inorganic filler is a silicon oxide having crystallinity, and the second inorganic filler contains at least one of alumina, titania, zirconia, ceria, forsterite, or an inorganic oxide pigment. The photosensitive insulating paste contains the first inorganic filler in an amount of from 10% by volume to 40% by volume and the second inorganic filler in an amount of from 0% by volume to 30% by volume, with the total of the glass frit, the first inorganic filler, and the second inorganic filler being 100% by volume.