Multilayer Electronics Embedding via High-Temp Bonding
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Solution Overview
Problem
Conventional multilayer electronics assembly methods fail to effectively embed discrete electrical circuit components due to the inability of conventional attachment methods to survive the temperature and pressure of fusion bonding, leading to limited packaging density and immunity to moisture ingress.
Innovation Solution
The use of a bonding material with an initial transition temperature lower than the glass transition temperature of the substrate layers, which undergoes a state transition to become flowable at a higher temperature, allowing for the embedding of discrete components within a multilayer module through nanosilver sintering or transient liquid phase bonding, ensuring the components remain bonded during fusion bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional attachment methods (solder paste) are used to attach discrete components, then the components can be attached to the substrate, but the attachment cannot withstand the temperature and pressure of fusion bonding process
Solution Approach 1:
The patent applies parameter changes by using a bonding material with a melting point specifically selected to be higher than the fusion bonding temperature (e.g., aluminum nitride with melting point >2000°C while fusion bonding occurs at 400-600°C). This parameter mismatch ensures the bonding material remains solid and stable during the fusion bonding process, resolving the contradiction between attachment reliability and fusion bonding temperature
Solution Approach 2:
The patent uses composite materials by combining the bonding material (e.g., aluminum nitride) with the substrate material (fluoropolymer composite) to create a multilayer structure where each material performs its optimal function - the bonding material provides heat-resistant attachment while the fluoropolymer substrate provides electrical insulation and structural support
2Quantity of substance
If discrete components are attached post-fusion bonding within cavities, then the components can be incorporated into the multilayer structure, but the packaging density is limited and additional processing steps are required
Solution Approach 1:
The patent applies preliminary action by attaching the discrete components to the substrate layers before the fusion bonding process. This allows the components to be embedded within the multilayer structure during a single bonding operation, eliminating the need for post-fusion bonding cavity formation and component insertion steps
Solution Approach 2:
The patent merges multiple operations into one by combining the component attachment process with the substrate bonding process. The discrete components are attached to substrates that are then bonded together in a single fusion bonding step, integrating what would traditionally be separate operations into a unified manufacturing process
3Ease of manufacture
If bonding material with low melting point is used to attach discrete components, then the components can be attached at lower temperatures, but the bonding material cannot withstand the high temperature of fusion bonding process
Solution Approach 1:
The patent applies parameter changes by selecting a bonding material with extremely high melting point (e.g., aluminum nitride >2000°C) that creates a large temperature gap between the attachment process temperature and the fusion bonding temperature. This allows the bonding material to remain stable throughout both processes without degrading
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 enhances packaging density and performance by allowing three-dimensional embedding of discrete components, reducing circuit parasitics, and improving moisture immunity, particularly in high-frequency applications.
Implementation Method 1
a bonding material having an initial transition temperature lower than a glass transition temperature of the layers of the multilayer structure to which the discrete components are attached, and goes through a state transition following processing to attach the discrete components
Implementation Method 2
embedding of discrete components within a multilayer module through nanosilver sintering or transient liquid phase bonding
Implementation Method 3
embedding of discrete components within a multilayer module through nanosilver sintering or transient liquid phase bonding
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3C
AI summary
A multilayer electronics assembly and associated method of manufacture are provided. The multilayer electronics assembly includes a plurality of stacked substrate layers. Each of the substrate layers is fusion bonded to at least an adjacent one of the plurality of substrate layers. A first discrete electrical circuit component is bonded to a first layer of the plurality of layers. A bonding material is interposed between the discrete electrical circuit component and the first layer. The bonding material has a reflow temperature at which the bonding material becomes flowable that is higher than a fusion bonding temperature of the substrate layers.