Circuit Board Capacitor Via Design for Drilling Stress Reduction
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Solution Overview
Problem
Existing circuit board manufacturing techniques that incorporate capacitors face issues with stress-induced deformation and crack generation during drilling, leading to reduced reliability and performance due to the differences in physical properties of the layers and adhesion properties, which can result in exfoliation and capacitance loss when heated.
Innovation Solution
The proposed solution involves forming a circuit board with a capacitor structure that includes a dielectric layer sandwiched between conductor layers, where the conductor layers have recessed areas and opening parts, allowing for a conductor via to penetrate without contacting the opening part, thereby reducing stress during drilling and preventing crack formation. This is achieved by drilling through the recessed areas of the conductor layers, which are thinned at the outer edge of the drilling position, and using a plating method to form the conductor via, ensuring electrical coupling without disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductor via is formed by drilling through the capacitor and forming conductor via material in the hole, then interlayer coupling is achieved, but stress-induced deformation and crack generation occur due to differences in physical properties of layers
Solution Approach 1:
The conductor layers are thinned at the outer edge of the drilling position before drilling occurs. This preliminary thinning action prevents stress concentration and crack generation during the drilling process, thereby maintaining manufacturing precision and capacitor reliability
Solution Approach 2:
The conductor layers are selectively thinned only at specific locations (outer edge of drilling position) rather than uniformly throughout. This local modification reduces stress during drilling without compromising the overall structural integrity and electrical functionality of the capacitor
2Reliability
If a conductor via penetrates the capacitor making contact with the dielectric layer, then electrical coupling is achieved, but exfoliation and capacitance loss occur when heated
Solution Approach 1:
The conductor via is configured to penetrate the dielectric layer without making contact with it. By extracting the contact interaction between the conductor via and dielectric layer, the invention eliminates the source of stress that causes exfoliation and capacitance loss during heating, while maintaining necessary electrical coupling through contact with conductor layers only
3Manufacturing precision
If the conductor layers are thinned at the outer edge of drilling position, then stress during drilling is reduced, but additional manufacturing steps are required
Solution Approach 1:
The thinning of conductor layers at the drilling position is combined with the existing conductor layer formation process. By merging the thinning operation with the conductor layer deposition or patterning step, the invention achieves crack prevention without significantly increasing manufacturing process complexity
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 approach enhances the reliability and performance of the circuit board by minimizing stress during drilling, preventing crack generation, and maintaining capacitance stability even under heating conditions, resulting in improved reliability and performance.
Implementation Method 1
using a plating method to form the conductor via
Data Source
AI summary
A circuit board includes: an insulating layer; a capacitor which is provided in the insulating layer and which includes a dielectric layer, a first conductor layer provided on a first surface of the dielectric layer and including an opening part, and a second conductor layer provided on a second surface opposite to the first surface of the dielectric layer and including a recess part at a position corresponding to the opening part; and a conductor via provided in the insulating layer, penetrating the dielectric layer, the opening part and the recess part, being in contact with the recess part, and being smaller than the opening part in plan view.