Wiring Board Crest Trough Arrangement Crack Prevention
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Solution Overview
Problem
The challenge is to prevent cracks in the insulating layer of wiring boards due to thermal stress caused by semiconductor chips, which can lead to voltage fluctuations and deteriorate electric characteristics, especially as semiconductor devices are downsized and thinned.
Innovation Solution
The wiring board design includes specific wiring arrangements with crests and troughs on the side faces of the ground and power planes, and insulating layers between them, ensuring that these planes are not overlapped in the thickness direction to prevent voltage fluctuations and crack propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wirings are disposed adjacently in plane direction, then crack spread is restrained, but voltage fluctuation deteriorates electric characteristics
Solution Approach 1:
The patent transitions from two-dimensional plane arrangement to three-dimensional arrangement by utilizing the thickness direction. Wirings are disposed adjacently in the thickness direction with crests and troughs providing vertical separation. This dimensional change allows crack restraint through adjacent disposition while preventing voltage fluctuation interference through non-overlapping arrangement in the vertical dimension.
Solution Approach 2:
The crests and troughs act as intermediary structures between adjacently disposed wirings. These features provide physical separation and electrical isolation while allowing the wirings to remain adjacently positioned for crack restraint. The intermediary crests and troughs enable the wirings to achieve crack resistance without direct contact that would cause voltage fluctuation problems.
2Volume of moving object
If semiconductor chip is downsized and thinned, then device size is reduced, but thermal stress increases causing insulating layer cracks
Solution Approach 1:
The patent segments the insulating layer into multiple regions separated by crests and troughs. This segmentation creates multiple small insulating sections rather than one large continuous layer, which reduces the propagation path for cracks. When thermal stress occurs due to downsized semiconductor chips, the segmented structure prevents crack spread across the entire board by confining potential cracks to individual segments.
Solution Approach 2:
The patent creates a composite structure combining the insulating layer with protruding and recessed portions (crests and troughs). This composite configuration provides both mechanical reinforcement against thermal stress and crack propagation resistance. The crests and troughs act as stress distribution features that prevent concentration of thermal stress in single locations, thereby preventing insulating layer cracks despite device downsizing.
Data Source
AI summary
A wiring board includes: a first wiring; a second wiring being disposed adjacently to the first wiring; a third wiring being disposed adjacently to the first wiring; a fourth wiring being disposed adjacently to the third wiring; and an insulating layer, wherein the second wiring and the fourth wiring are disposed adjacently to each other, the first wiring and the fourth wiring are not overlapped, the second wiring and the third wiring are not overlapped, a crest and a trough are provided on a side face of the first wiring, the crest and the trough are provided on a side face of the second wiring, the trough provided on the side face of the first wiring and the third wiring are overlapped, and the trough provided on the side face of the second wiring and the fourth wiring are overlapped.