Wiring Circuit Board Via Layout for Low-Resistance Grounding
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Solution Overview
Problem
Existing wiring circuit boards face issues with high resistance in ground connections due to large via hole diameters, leading to potential gaps and connection failures with solder bumps, which affect connectivity and wiring density.
Innovation Solution
A wiring circuit board design featuring a terminal portion with a via-on-pad (VOP) structure, including a first via portion connected to the metal supporting board and a tail line portion with a second via portion, which reduces resistance while suppressing via diameter enlargement, ensuring good connectivity and high-density wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the via hole diameter is increased to reduce ground connection resistance, then the resistance decreases, but the recess size increases causing gaps and connection failures with solder bumps
Solution Approach 1:
The invention divides the single via hole into multiple via holes (first via holes and second via holes) within the terminal portion. This segmentation allows the total conductive area to be increased for low resistance while keeping individual via hole diameters small to avoid excessive recess formation. The multiple small via holes collectively provide the necessary ground connection area without the drawbacks of a single large via hole.
Solution Approach 2:
The invention applies different via hole configurations to different regions: the terminal portion contains multiple via holes (first and second via holes) with specific diameter ratios to optimize both resistance and recess control, while the tail line portion uses a different via hole structure. This local differentiation allows optimization of each region's specific requirements - the terminal portion for low resistance with controlled recess, and the tail line for appropriate impedance control.
2Reliability
If the via hole diameter is increased to achieve low-resistance ground connection, then the resistance decreases, but the wiring density decreases due to larger recess areas
Solution Approach 1:
The terminal portion is segmented into multiple via holes instead of using a single large via hole. This segmentation increases the effective conductive area for ground connection (reducing resistance) while the individual via holes remain small enough to maintain high wiring density. The multiple small via holes occupy less total area than one large via hole would require.
3Productivity
If the via hole diameter is kept small to maintain wiring density, then the wiring density increases, but the ground connection resistance increases
Solution Approach 1:
The invention merges multiple via holes (first via holes and second via holes) within the terminal portion to create a composite conductive structure. While each individual via hole remains small to maintain wiring density, their combined effect provides sufficient total conductive area to achieve low ground connection resistance. The merging of multiple small conductive paths equals or exceeds the performance of a single large via hole.
Solution Approach 2:
The invention changes the parameter of via hole quantity from one to multiple, and optimizes the diameter ratio between first and second via holes. This parameter change allows the system to achieve low resistance through increased total conductive area while maintaining small individual via hole diameters for high wiring density and controlled recess formation.
4Productivity
If a pad-on-via structure is used to achieve high-density wiring, then the wiring density increases, but the connection reliability to external components decreases due to recess gaps
Solution Approach 1:
The terminal portion uses a segmented via structure with multiple first via holes and second via holes instead of a single pad-on-via structure. This segmentation allows the terminal to maintain high wiring density while the combined via structure provides sufficient support area to prevent recess gaps and ensure reliable solder bump connection.
Data Source
AI summary
A wiring circuit board includes a metal supporting board; an insulating layer; and a conductive layer in this order in a thickness direction. The conductive layer includes a terminal portion, and a tail line portion extending from the terminal portion. The terminal portion has a via portion that penetrates the insulating layer in the thickness direction and is connected to the metal supporting board. The tail line portion has a base end portion that has a width different from a width of the terminal portion in a direction orthogonal to the extending direction of the tail line portion and that is connected with the terminal portion; and a second via portion that penetrates the insulating layer in the thickness direction and that is connected to the metal supporting board.