Paper Ceramic Substrate with Adhesive-Filled Pores for Isolation Strength
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Solution Overview
Problem
Conventional substrates for electrical circuits, particularly in power electronics, face challenges with complex and costly manufacturing processes and degradation of isolation strength due to porosity in ceramic materials used in metal ceramic substrates.
Innovation Solution
A substrate with a paper ceramic layer produced using a two-step thermal process, where an adhesive is applied to fill surface-side cavities, reducing porosity to less than 10% and enhancing isolation strength, and connected to metal layers via adhesive layers for improved mechanical stability and low voltage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ceramic layers are used in metal ceramic substrates to achieve high isolation strength, then the isolation strength is improved, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent changes the material parameters by using paper ceramic instead of conventional ceramic layers. The paper ceramic is produced with controlled porosity (less than 50% initially, then reduced to less than 10% after adhesive filling) and specific material composition (cellulose fibers with ceramic filler), which maintains isolation strength while enabling simpler manufacturing processes and shaping capabilities.
Solution Approach 2:
The patent employs composite materials by combining cellulose fibers with ceramic filler materials (such as Al2O3, Si3N4, AlN, ZrO2, MgO, SiC, or BeO) to create paper ceramic. This composite structure provides both the mechanical properties needed for substrate applications and the electrical isolation properties required, while allowing for simpler processing compared to conventional ceramics.
2Ease of manufacture
If paper ceramic is used to simplify manufacturing and shaping, then ease of manufacture is improved, but porosity increases and degrades isolation strength
Solution Approach 1:
The patent applies local quality by using adhesive layers selectively to fill the cavities and pores in the paper ceramic structure. The adhesive is applied in specific amounts and locations (on the surface side of the paper ceramic layer) to reduce porosity locally where it most affects isolation strength, while maintaining the overall shaping advantages of paper ceramic. This targeted approach reduces porosity to less than 10% in critical areas without compromising the manufacturing simplicity.
Solution Approach 2:
The patent introduces an adhesive layer as an intermediary substance between the metal layer and the paper ceramic layer. This adhesive serves multiple functions: it provides mechanical bonding, fills the pores and cavities in the paper ceramic to reduce porosity, and improves the isolation strength. The adhesive acts as a mediator that compensates for the inherent porosity of paper ceramic while maintaining the ease of manufacture and shaping capabilities.
3Reliability
If adhesive layers are applied to fill cavities and reduce porosity, then isolation strength is improved, but manufacturing steps increase
Solution Approach 1:
The patent merges multiple functions into the adhesive layer application step. The adhesive is applied not only to bond the metal layer to the paper ceramic layer but also to fill the cavities and pores simultaneously. This combined approach achieves both mechanical bonding and porosity reduction in a single manufacturing step, rather than requiring separate operations for bonding and pore filling, thus limiting the increase in manufacturing complexity.
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 method allows for a cost-efficient production of substrates with improved isolation strength and mechanical stability, suitable for low voltage applications, while maintaining a lightweight and shapeable material for easier processing.
Implementation Method 1
the cavities in the form of pores in the paper ceramic layer are filled at least on the surface side
Implementation Method 2
organic components of the pre-ceramic papers, such as pulp, starch and latex, are removed by oxidation
Implementation Method 3
the brown compact is sintered in a second step of the thermal implementation, thereby generating a ceramic substance
Data Source
AI summary
A substrate (1, 10) for electrical circuits, comprising at least one metal layer (2,3, 14) and a paper ceramic layer (11), which is joined face to face with the at least one metal layer (2,3, 14) and has a top side and bottom side (11a, 11b), wherein the paper ceramic layer (11) has a large number of cavities in the form of pores. Especially advantageously, the at least one metal layer (2, 3, 14) is connected to the paper ceramic layer (11) by means of at least one glue layer (6, 6a, 6b), which is produced by applying at least one glue (6a′, 6a″, 6b′, 6b″) to the metal layer (2,3, 14) and/or to the paper ceramic layer (11), wherein the cavities in the form of pores in the paper ceramic layer (11) are filled at least at the surface by means of the applied glue (6a′, 6a″, 6b′,6b″).