Resin Multilayer Substrate with Uneven Ground Conductor Openings
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Solution Overview
Problem
Resin multilayer substrates with large metal patterns face delamination issues due to trapped gases during heating, which can degrade electrical characteristics and affect mountability, as conventional degassing methods compromise transmission line integrity.
Innovation Solution
The substrate features a ground conductor with unevenly distributed openings perpendicular to the laminating direction, with a higher aperture ratio in zones farther from the signal line, allowing effective degassing while minimizing impact on electrical characteristics, and includes interlayer connecting conductors for enhanced shielding and gas escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large area ground conductor is provided for shielding, then electromagnetic shielding performance is improved, but gas discharge paths are blocked causing delamination
Solution Approach 1:
The ground conductor is designed with multiple openings (through-holes) distributed across its surface, transforming it from a solid continuous structure to a porous-like structure. This allows gas to pass through the ground conductor during heating and lamination, preventing gas accumulation and delamination while maintaining the ground conductor's shielding function.
Solution Approach 2:
The ground conductor is segmented by introducing multiple openings that divide the continuous metal pattern into separate regions. These openings create multiple gas discharge paths through the ground conductor, allowing trapped gas to escape during heating without compromising the overall shielding effectiveness of the large-area ground conductor.
2Reliability
If openings are provided in the ground conductor for gas discharge, then delamination is reduced, but transmission line electrical characteristics are degraded
Solution Approach 1:
The openings are non-uniformly distributed across the ground conductor, with different densities in different regions. The aperture ratio (proportion of opening area to total area) varies locally to optimize both gas discharge performance and electrical characteristic maintenance. This local variation allows different parts of the ground conductor to serve different functions: regions with higher aperture ratios facilitate gas discharge, while regions with lower aperture ratios maintain electrical performance.
3Reliability
If uniform openings are distributed across the ground conductor, then gas discharge is improved, but electrical characteristics become uneven
Solution Approach 1:
The opening distribution is optimized locally rather than uniformly. The aperture ratio is adjusted in different regions based on their specific requirements: areas closer to signal lines have lower aperture ratios to maintain electrical characteristics, while areas farther from signal lines have higher aperture ratios to enhance gas discharge. This local optimization resolves the contradiction between gas discharge efficiency and electrical characteristic uniformity.
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 design reduces delamination and maintains electrical characteristics, improving mountability by efficiently releasing gases and stabilizing the transmission line's electrical performance.
Implementation Method 1
when a resin base material of a multilayer substrate receives heat at a predetermined temperature or higher, a portion of the resin base material is thermally decomposed to generate gas such as CO2 and water
Implementation Method 2
oxygen resulting from a reduction reaction of oxidized conductor patterns due to the heat and carbon in the thermoplastic resin undergo an oxidation reaction to generate CO2
Implementation Method 3
A plurality of openings are provided in the ground conductor to provide an unevenly distributed aperture ratio. The openings are provided, in a direction perpendicular or substantially perpendicular to the laminating direction
Implementation Method 4
the gas or vapor expands to cause delamination. Accordingly, in the formation of the multilayer substrate, heating and pressurization are typically performed under reduced pressure and a predetermined preheating step is provided, which allows the gas to be discharged to the outside of the laminate
Data Source
AI summary
A resin multilayer substrate includes a plurality of insulating resin base material layers and a plurality of conductor patterns provided on the plurality of insulating resin base material layers. The plurality of conductor patterns include a signal line and a ground conductor overlapping the signal line as viewed from a laminating direction of the insulating resin base material layers. A plurality of openings are provided in the ground conductor, and an aperture ratio is higher in a zone far from the signal line than in a zone adjacent to or in a vicinity of the signal line in a direction perpendicular or substantially perpendicular to the laminating direction.