Resin Multilayer Substrate Cavity Boundary Reinforcement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multilayer substrates with resin insulating layers are prone to cracking due to bending stress, especially at the boundary between the side and bottom surfaces of cavities, where the bonding strength between conductor patterns and insulating substrate layers is weak.
Innovation Solution
A resin multilayer substrate design where the boundary between the side and bottom surfaces of the cavity includes a continuous conductor pattern with a higher Young's modulus than the insulating substrate layers, reducing bending stress and preventing cracks, and additional features such as interlayer connection conductors and specific conductor pattern thickness and surface roughness configurations are implemented to enhance mechanical strength and bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a cavity is formed in a stacked body with insulating substrate layers, then components can be disposed in the cavity, but bending stress concentrates at the boundary between the side surface and bottom surface of the cavity, causing cracks
Solution Approach 1:
The conductor pattern is specifically designed to extend continuously from the bottom surface to the side surface of the cavity, creating a localized reinforcement zone at the boundary where bending stress concentrates. This continuous conductor pattern provides both mechanical strength and electrical connectivity at the critical interface between the cavity structure and the insulating substrate layers.
Solution Approach 2:
The cavity boundary structure utilizes a composite configuration combining the conductor pattern material with the insulating substrate layers. The conductor pattern serves dual functions: maintaining electrical continuity and providing mechanical reinforcement at the stress-concentration zone, while the insulating substrate layers provide structural support and electrical insulation.
2Volume of moving object
If the stacked body is made thinner to reduce overall size, then the device becomes more compact, but the stacked body becomes more easily deformed by external forces, increasing crack likelihood at the cavity boundary
Solution Approach 1:
The conductor pattern is segmented into regions with different thicknesses: a first region embedded in the insulating substrate layers and a second region exposed on the bottom surface of the cavity. This segmentation allows the conductor pattern to provide reinforcement at the cavity boundary while maintaining overall device compactness.
Solution Approach 2:
The conductor pattern thickness is locally optimized at the cavity boundary, where it extends continuously from the bottom surface to the side surface. This localized thickening provides targeted mechanical reinforcement at the stress-concentration zone without increasing the overall thickness of the stacked body.
3Strength
If the conductor pattern is made thicker to increase mechanical strength, then crack resistance improves, but the Young's modulus difference between conductor and insulating layers increases, potentially causing deformation
Solution Approach 1:
The conductor pattern is configured with different thicknesses in different regions: the first region embedded in the insulating substrate layers has a certain thickness, while the second region exposed on the bottom surface has a greater thickness. This local quality variation provides mechanical strength where needed while controlling overall deformation.
Solution Approach 2:
The conductor pattern thickness is optimized to balance mechanical strength and deformation control. The continuous conductor pattern from bottom surface to side surface provides reinforcement against bending stress, while the specific thickness configuration ensures the Young's modulus difference does not cause excessive deformation.
Data Source
AI summary
A resin multilayer substrate includes a stacked body including a first main surface, a cavity provided in the first main surface, and conductor patterns provided in the stacked body. The stacked body includes insulating substrate layers including resin as a main material that are stacked. The cavity includes a side surface and a bottom surface. At least a portion of a boundary between the side surface and the bottom surface includes conductor patterns continuous with the side surface and the bottom surface.