Offset Cermet Feedthroughs in Multilayer Ceramic Bodies
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Solution Overview
Problem
Existing cermet feedthroughs in implantable medical devices face challenges with non-congruent top and bottom cermet contacts, requiring additional process steps and risking delamination due to air gaps, which complicates the production and reduces the reliability and durability of the devices.
Innovation Solution
A cermet feedthrough design within a ceramic multilayer body where the cermet contacts are connected through intermediate cermet elements via partial overlap, eliminating the need for additional conductive layers and ensuring hermeticity, biocompatibility, and high conductivity without additional process steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional conductive layers are provided between green sheet interfaces to bridge horizontal offset, then electrical connection between non-congruent cermet contacts is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent transitions from a 2D planar connection approach to a 3D spatial arrangement by allowing intermediate cermet elements to extend vertically across multiple green sheet interfaces. This dimensional change enables electrical connection through the thickness direction rather than requiring additional lateral conductive layers, thus bridging horizontal offsets without increasing planar complexity.
Solution Approach 2:
The intermediate cermet elements are nested within the stack of green sheets, with each intermediate cermet element positioned to bridge the horizontal offset between cermet elements of adjacent green sheets. This nesting approach integrates the connection function within the existing layered structure rather than adding separate external connection layers.
2Ease of manufacture
If conventional LTCC or HTCC techniques are used with non-congruent cermet contacts, then production process is simplified, but air gaps and delamination risks increase
Solution Approach 1:
The intermediate cermet elements act as intermediary components that fill the spatial gap created by horizontal offsets between non-congruent cermet contacts. These intermediates provide both mechanical support to prevent air gap formation and electrical continuity, mediating between the offset contacts while maintaining hermeticity without requiring additional process steps.
3Reliability
If multiple intermaterial connections are made in traditional feedthroughs, then electrical connectivity is achieved, but connection reliability decreases due to more potential failure points
Solution Approach 1:
The patent merges multiple connection functions into a single integrated ceramic body structure. The intermediate cermet elements are formed as part of the same sintering process, creating a unified structure where electrical connections are achieved through monolithic ceramic material rather than through multiple separate intermaterial joints, thereby reducing potential failure points.
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 enhances the reliability and durability of implantable medical devices by maintaining hermeticity and high conductivity while simplifying the production process, reducing defects, and improving biocompatibility.
Implementation Method 1
firing the sequence of ceramic green sheets thereby obtaining a composite comprising a ceramic body and a cermet conductor
Implementation Method 2
at least one cermet conductor that electrically connects the first layer surface and the second layer surface
Data Source
Figure 1A)~1B)
Figure 2
Figure 3
AI summary
The present invention generally relates to a composite, comprising a ceramic body having a first layer surface and a second layer surface and at least one cermet conductor that electrically connects the first layer surface and the second layer surface, wherein the composite has a layer sequence that comprises as layers i) a first layer with the first layer surface, wherein the first layer comprises a first ceramic, a first hole and a first cermet element comprised in the first hole, ii) a second layer with the second layer surface, wherein the second layer comprises a second ceramic, a second hole and a second cermet element comprised in the second hole, iii) at least one intermediate layer that is located between the first and the second layer, wherein the et least one intermediate layer comprises an intermediate layer ceramic, at least one intermediate hole and at least one intermediate cermet element comprised in the at least one intermediate hole, wherein a projection of the cross-section of the first hole and a projection of the cross section of the second hole onto a plane Px,y are arranged offset to each other, wherein the ceramic body comprises the ceramic of the individual layers and wherein the at least one cermet conductor is an electrical connection between the first cermet element and the second cermet element via the at least one intermediate cerment element and wherein the electrical connection is accomplished by an at least partial overlap of cermet elements in layers that are located adjacent to each other. The invention also related to a process for the preparation of a composite, to the composite obtainable by such a process and to the used of a composite.