Platinum Pad Welding for Hermetic Feedthrough Biostability
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Solution Overview
Problem
Hermetic feedthroughs for implantable medical devices face challenges in maintaining long-term biostability and biocompatibility, particularly in preventing leakage of bodily fluids and ensuring high electrical conductivity over extended periods.
Innovation Solution
The method involves welding a lead to a pad on a hermetic feedthrough using a ceramic insulator with a via hermetically bonded to the insulator, where the pad and via are made of platinum, and the lead is composed of materials like niobium, platinum, titanium, or their alloys, ensuring a strong and reliable connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pad thickness is increased to at least 50 μm, then mechanical strength is improved, but manufacturing complexity increases
Solution Approach 1:
The thick pad structure is incorporated into the ceramic feedthrough during the initial manufacturing process (co-firing), rather than being added as a separate post-processing step. This preliminary integration of the thick pad layer into the ceramic fabrication process achieves the required mechanical strength while avoiding additional manufacturing complexity, as the pad and ceramic are formed together in a single integrated process.
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 results in a biocompatible and biostable feedthrough that maintains hermeticity and high electrical conductivity, preventing fluid leakage and ensuring the device's functionality for years without significant degradation.
Implementation Method 1
joining a lead to a pad on a feedthrough using a laser
Data Source
AI summary
A method of interconnecting a conductor and a hermetic feedthrough of an implantable medical device includes welding a lead to a pad on a feedthrough. The feedthrough includes a ceramic insulator and a via hermetically bonded to the insulator. The via includes platinum. The pad is bonded to the insulator and electrically connected to the via, includes platinum, and has a thickness of at least 50 μm. The lead includes at least one of niobium, platinum, titanium, tantalum, palladium, gold, nickel, tungsten, and oxides and alloys thereof.