Multi-layer PCB Insulation with Graded Fillers
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Solution Overview
Problem
The miniaturization of printed circuit boards (PCBs) leads to challenges in forming high-performance semiconductor devices due to issues with insulation structures, including high dielectric loss, increased coefficient of thermal expansion, and reduced adhesion strength, which affect the integration and miniaturization of devices.
Innovation Solution
A multi-layer insulation structure comprising epoxy resin layers with varying sizes of inorganic fillers, where each layer has a specific thickness and filler diameter, optimized to achieve low surface roughness and improved adhesion, thereby reducing dielectric loss and thermal expansion while maintaining mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the PCB is miniaturized to obtain high performance, then the device size is reduced, but the insulation structure exhibits high dielectric loss and reduced adhesion strength
Solution Approach 1:
The patent employs a multi-layer composite insulation structure where each layer contains resin mixed with inorganic fillers of specific size ranges. The first layer uses fillers of 0.5-5 μm, the second layer uses 0.05-0.5 μm, and the third layer uses 5-50 nm fillers. This composite approach with progressively smaller fillers in each layer reduces dielectric loss while maintaining mechanical properties, enabling miniaturization without performance degradation.
2Volume of moving object
If the PCB is miniaturized, then the device size is reduced, but the insulation structure exhibits increased coefficient of thermal expansion
Solution Approach 1:
The multi-layer composite insulation structure with progressively smaller inorganic fillers (0.5-5 μm in first layer, 0.05-0.5 μm in second layer, 5-50 nm in third layer) effectively controls the coefficient of thermal expansion. The combination of different filler sizes and types in each layer creates a composite material with optimized thermal expansion properties, allowing miniaturization while maintaining thermal stability.
3Volume of moving object
If the insulation structure is designed for miniaturization, then the PCB size is reduced, but the adhesion strength of the insulation structure is reduced
Solution Approach 1:
The patent uses composite materials with resin and inorganic fillers of controlled size distribution across three layers. The first layer (0.5-5 μm fillers) provides structural support and adhesion, the second layer (0.05-0.5 μm fillers) transitions properties, and the third layer (5-50 nm fillers) reduces surface roughness. This composite structure maintains strong adhesion to copper foils even as the overall PCB size is reduced.
4Ease of manufacture
If the insulation structure uses uniform filler sizes, then the manufacturing process is simplified, but the surface roughness increases
Solution Approach 1:
The patent segments the insulation structure into three distinct layers, each with progressively smaller filler sizes. The first layer contains 0.5-5 μm fillers, the second layer contains 0.05-0.5 μm fillers, and the third layer contains 5-50 nm fillers. This segmentation allows each layer to contribute differently to the overall surface roughness, with the finest fillers in the top layer achieving Ra ≤ 30 nm and Rz ≤ 100 nm, while the lower layers provide structural support.
Data Source
AI summary
An insulation structure includes: a first resin layer including first fillers; a second resin layer on the first resin layer and including second fillers; and a third resin layer on the second resin layer and including third fillers. A diameter of each of the first fillers may be more than about 200 nm and equal to or less than about 500 nm. A diameter of each of the second fillers may be more than about 10 nm and equal to or less than about 200 nm. A diameter of each of the third fillers may be equal to or less than about 10 nm. An arithmetic average roughness (Ra) and a ten point average roughness (Rz) of a surface of the insulation structure may be equal to or less than about 30 nm and equal to or less than about 100 nm, respectively.