Composite Substrate with Integral Resin Layers for Adhesive Strength
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Solution Overview
Problem
Ceramic multilayer substrates with resin layers for mobile communication modules face issues with adhesive strength, leading to peeling between the resin and ceramic layers due to shock, impact, or thermal stress, as the interface between these layers is exposed and lacks sufficient bonding.
Innovation Solution
A composite substrate design featuring an upper and lower ceramic layer with a middle resin layer sandwiched between them and a side surface resin layer covering all sides, where the middle and side surface resin layers are integral, formed through a process involving cavity formation, resin immersion, and curing to enhance bonding and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin layer is formed in a ceramic multilayer substrate to reduce size, height, and transmission loss, then the substrate meets mobile communication requirements, but the adhesive strength at the interface between the resin layer and ceramic layer is insufficient, causing peeling under shock, impact, or thermal stress
Solution Approach 1:
The invention extends the resin layer from the internal interface region to the external surface region, transforming a two-dimensional internal bonding problem into a three-dimensional structure that includes surface coverage. This dimensional extension allows the resin layer to wrap around and cover the side surfaces of the ceramic layers, creating additional bonding surfaces and distributing stress more effectively across multiple dimensions, thereby preventing peeling at the original interface.
Solution Approach 2:
The resin layer is formed to protrude from the side surfaces of the ceramic layers before final assembly and mounting operations. This preliminary extension of the resin layer allows it to establish bonding contact with external structures or mounting surfaces in advance, creating pre-stressed adhesive bonds that counteract subsequent thermal and mechanical stresses during operation and reflow processes.
2Device complexity
If the interface between the resin layer and ceramic layer is exposed on side surfaces, then the substrate structure is simple, but the adhesive strength is insufficient and peeling occurs
Solution Approach 1:
The resin layer serves multiple functions simultaneously: it provides electrical insulation between ceramic layers, provides adhesive bonding to prevent peeling, and extends to cover side surfaces to provide additional mechanical reinforcement and environmental protection. This multi-functionality is achieved by making the resin layer protrude from the side surfaces, allowing a single material component to fulfill several protective and structural roles that would otherwise require separate elements.
3Reliability
If the resin layer protrudes from side surfaces to cover them, then adhesive strength improves and peeling is prevented, but the substrate height increases
Solution Approach 1:
The resin layer is designed with non-uniform thickness, being thicker at the side surface regions where it protrudes from the ceramic layers and thinner in the central insulation regions. This local variation in quality allows the resin to provide maximum bonding coverage where needed (at the interfaces and side surfaces) while minimizing the overall height increase. The local concentration of resin material at critical bonding zones achieves the reliability improvement without requiring uniform thickening throughout the entire substrate structure.
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 integrated resin layers improve the substrate's strength against shock and impact, reduce peeling risks, and maintain low transmission loss, ensuring reliable performance in high-frequency applications.
Implementation Method 1
immersing the substrate with the cavity in a liquid containing a resin material to cause the resin material to adhere to the cavity and all side surfaces of the substrate
Implementation Method 2
curing the resin material to form a middle resin layer between the upper ceramic layer and the lower ceramic layer and a side surface resin layer entirely on all side surfaces of the substrate
Data Source
AI summary
A composite substrate that includes: an upper ceramic layer; a lower ceramic layer; a middle resin layer between the upper ceramic layer and the lower ceramic layer; and a side surface resin layer on all side surfaces of the composite substrate, wherein the middle resin layer and the side surface resin layer are integral resin layers.