Wiring Substrate Staggered Via Conductors Thermal Stress
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Solution Overview
Problem
The existing wiring substrates are prone to cracks and short circuits due to stress caused by the difference in thermal expansion coefficients between the insulating layers and via conductors, especially when via conductors are arranged linearly, leading to undesirable electrical connectivity.
Innovation Solution
The wiring substrate features via conductors arranged in a staggered or zigzag pattern across multiple layers, with varying numbers and orientations to prevent linear alignment, using ceramic layers and conductive materials like tungsten or molybdenum, and shifting angles between groups of via conductors to distribute stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If via conductors are arranged linearly or in a straight line in plan view, then electrical connectivity between pads is improved, but stress concentrates along the linearly-arranged via conductors causing cracks and short circuits
Solution Approach 1:
The patent applies asymmetry by arranging via conductors in non-linear, staggered patterns rather than straight lines. Specifically, via conductors connecting adjacent pads are offset from linear alignment, creating asymmetric stress distribution that prevents stress concentration and crack formation while maintaining electrical connectivity between pads across insulating layers
Solution Approach 2:
The patent transitions from one-dimensional linear arrangement to two-dimensional staggered arrangement of via conductors. By distributing via conductors across different positions in the plan view and creating offset patterns between adjacent pads, the design adds spatial dimensionality to the via conductor layout, effectively reducing stress concentration while preserving electrical pathways
2Strength
If via conductors are arranged in a staggered or zigzag pattern, then stress distribution is improved and cracks are reduced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the via conductor arrangement into distinct groups associated with different pads, where each group's position is independently determined. This segmentation allows the via conductors to be arranged in staggered patterns that simplify stress distribution while maintaining systematic manufacturability through modular pad-and-via group configurations
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 configuration reduces the likelihood of cracks and maintains high electrical connectivity by distributing stress and preventing linear alignment of via conductors, ensuring accurate size and shape of components and enhancing the substrate's electrical characteristics.
Implementation Method 1
a plurality of via conductors 9 penetrating an upper insulating layer and connecting to the pad and penetrating a lower insulating layer and connecting to the pad
Implementation Method 2
substrate body formed by a single or a plurality of insulating layers
Data Source
Figure 1A~1C
Figure 2~4
Figure 5A~5C
AI summary
A wiring substrate has a substrate body formed by a single or a plurality of insulating layers and having front and back surfaces located at opposite sides of the substrate body; a plurality of pads formed on at least one of the front surface, the back surface and an inner layer surface that is located between the front and back surfaces, and having a staggered arrangement in plan view; and a plurality of via conductors formed at each of the pads, extending in a thickness direction of the substrate body with the plurality of via conductors being parallel to each other and connecting the pads located on different surfaces. Arrangement, in plan view, of the plurality of via conductors connecting to the pad and arrangement, in plan view, of the plurality of via conductors connecting to an adjacent pad located on the same surface are different from each other.