Wiring Board Terminal Offset for Thermal Stress Management
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Solution Overview
Problem
Existing wiring boards with built-in electronic components face challenges in managing thermal stresses and connection reliability due to the direct formation of external connection terminals over pads, which can lead to quality degradation and reduced reliability, especially when integrated with components having low strength and low dielectric constants.
Innovation Solution
The design involves forming external connection terminals on the outer layer of a wiring board to avoid direct alignment over the pads and electronic component, with a substrate structure that includes laminated sections and offset terminal positions to mitigate stress propagation and enhance reliability, using a method that involves laminating insulation and conductive layers with specific pitch settings and via hole configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external connection terminals are formed directly over the pads of the electronic component, then electrical connection is simplified, but thermal stress concentration and quality degradation occur
Solution Approach 1:
The patent transitions from a two-dimensional planar arrangement where terminals are directly over pads to a three-dimensional offset arrangement. The first external connection terminal is positioned offset from the first pads in the lateral direction, while still maintaining electrical connection through conductive vias. This spatial reconfiguration in another dimension reduces thermal stress concentration on the pads while preserving electrical connectivity.
Solution Approach 2:
The patent introduces an intermediary structure - the first laminated section containing conductive vias and wiring layers - that mediates between the first pads and the first external connection terminal. This intermediary layer allows electrical connection while physically separating the terminal from the pad, thereby reducing direct thermal stress transmission from the terminal to the pad.
2Object-affected harmful factors
If external connection terminals are positioned offset from pads, then thermal stress is reduced, but wiring complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the wiring structure into distinct functional layers: the first laminated section containing conductive vias for vertical connection, intermediate wiring layers for signal routing, and the external connection terminal layer for external connectivity. This segmentation allows each layer to be optimized independently, managing complexity through modular design while achieving the offset configuration.
Solution Approach 2:
The patent employs a nested structure where conductive vias are embedded within the first laminated section, which itself is embedded within the substrate. The wiring layers are nested between insulating layers, creating a compact multi-layer configuration. This nesting approach reduces overall wiring complexity by organizing conductors in a hierarchical, space-efficient manner.
3Reliability
If multiple layers are laminated to achieve offset terminal positioning, then connection reliability improves, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-forming the first laminated section with embedded conductive vias and wiring patterns before mounting the electronic component. The offset terminal positions are predetermined in the laminated structure, allowing subsequent assembly steps to proceed without complex alignment operations. This preliminary preparation simplifies the overall manufacturing process despite the multi-layer complexity.
Solution Approach 2:
The patent merges multiple functions into the first laminated section: it serves as the insulating substrate for offset terminal positioning, contains the conductive vias for electrical connection, and provides mechanical support for the electronic component. This consolidation of multiple functions into a single integrated laminated structure reduces the number of separate manufacturing steps and simplifies the overall process.
Data Source
AI summary
A wiring board has a substrate designating one of the upper and lower surfaces as a first surface and the other as a second surface, a first laminated section laminated on the second-surface side of the substrate, a first external connection terminal and second external connection terminals formed on the first laminated section, and an electronic component arranged inside the substrate and having first pads on the second-surface side. The first pads and first terminal as well as the first pads and second terminals are electrically connected, and the first terminal and second terminals are formed to avoid being directly over the first pads. When the first pads, first terminal and second terminals are projected onto the second surface, the first terminal is positioned to be surrounded by the first pads, and the first pads and first terminal are positioned to be surrounded by the second terminals.