Low Permeability Electrical Feed-Through via Laminated Diffusion Channel
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Solution Overview
Problem
Hermetically sealed hard disk drives face challenges in minimizing gas leakage through electrical feed-throughs while maintaining cost-effectiveness, as existing solutions either offer high permeability and are expensive or have higher leak rates.
Innovation Solution
A low permeability electrical feed-through is designed with a laminated structure featuring a conductor layer sandwiched between insulator and diffusion control layers, forming a high aspect ratio diffusion channel to inhibit gas leakage, and includes specific via configurations for signal transmission lines to manage capacitance and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass-metal feed-through is used, then gas leakage is reduced, but cost increases
Solution Approach 1:
The patent employs a composite structure combining metal layers (conductive) and polymer layers (insulating and sealing) to create a feed-through that achieves hermetic sealing without requiring expensive glass-metal bonding. The metal layers provide electrical conductivity while the polymer layers provide insulation and gas barrier properties, collectively achieving low gas leakage at lower cost.
Solution Approach 2:
The patent modifies the permeability parameter by using a polymer layer with specifically controlled thickness and material properties to achieve the desired gas barrier performance. By adjusting the polymer layer parameters (thickness, material composition), the feed-through achieves low gas leakage rates comparable to glass-metal solutions but with reduced manufacturing complexity and cost.
2Ease of manufacture
If PCB feed-through is used, then cost is reduced, but gas leakage increases
Solution Approach 1:
The patent transforms a standard PCB feed-through into a low-permeability version by adding a polymer layer over the conductive trace. This composite structure maintains the electrical functionality of the PCB while the polymer layer provides the necessary gas barrier properties, achieving hermetic sealing at low cost.
Solution Approach 2:
The feed-through is segmented into distinct functional layers: a metal conductive layer for electrical conduction and a separate polymer layer for gas barrier and insulation. This segmentation allows each layer to be optimized for its specific function, achieving both electrical connectivity and gas leakage prevention in a cost-effective manner.
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 solution effectively reduces gas leakage from the sealed environment while maintaining electrical connectivity, achieving a balance between low permeability and cost-effectiveness by using a laminated structure with controlled diffusion channels and via configurations.
Implementation Method 1
the laminated structure provides a high aspect ratio diffusion channel (i.e., relatively narrow and long) to inhibit the leakage of gas from within the sealed device to the external environment
Data Source
AI summary
A low permeability electrical feed-through involves a laminated structure having a conductor layer sandwiched between adjacent insulator layers, which are sandwiched between adjacent diffusion control layers, where the laminated structure provides a relatively narrow and long, high aspect ratio diffusion channel to inhibit the leakage of gas from within a sealed device to the external environment. The electrical feed-through may comprise lower and upper electrical connection pads that are positioned within different regions of the feed-through but still electrically connected by way of a first via positioned in a sealed region, the conductor layer, and a second via positioned in an external environment region.