Three-Part Through Electrode Structure for Thick Circuit Boards
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Solution Overview
Problem
Conventional circuit boards with through electrodes in insulating layers of 300 μm or more face challenges such as voids and dimples due to difficulties in processing and filling conductive materials, leading to reliability issues in signal transmission, heat dissipation, and shielding functions.
Innovation Solution
A circuit board design featuring a through electrode with three distinct electrode parts, each with a specific inclination, forming a trapezoidal and rectangular shape, and a dense glass fiber region in the central insulating layer to enhance bonding and reliability, preventing voids and dimples through a post-plating process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through electrode is formed in an insulating layer with thickness of 300 μm or more, then signal transmission and heat dissipation functions are achieved, but voids and dimples occur leading to reliability degradation
Solution Approach 1:
The through electrode is divided into three distinct parts: a first electrode part adjacent to the lower surface, a second electrode part adjacent to the upper surface, and a third electrode part in the central region. This segmentation allows each part to be formed with optimized parameters, preventing voids and dimples that occur when forming a single continuous electrode through thick insulating layers.
Solution Approach 2:
The patent creates a dense glass fiber region specifically in the central third region of the insulating layer where the third electrode part is formed. This local modification of material density and composition enhances bonding in the critical central region, preventing void formation without affecting the overall structure unnecessarily.
2Strength
If the insulating layer thickness is increased to 300 μm or more, then heat dissipation and shielding functions are improved, but processing difficulty increases leading to voids and dimples
Solution Approach 1:
By segmenting the through electrode into three parts formed at different stages, the patent makes processing of thick insulating layers feasible. Each electrode part can be formed with appropriate parameters for its specific location, making the overall manufacturing process easier despite the increased thickness.
Solution Approach 2:
The third electrode part in the central region is formed first, followed by the first and second electrode parts. This preliminary action in the central region establishes a foundation that prevents void formation during subsequent processing steps.
3Productivity
If conventional through electrode formation is used, then manufacturing simplicity is maintained, but voids and dimples occur reducing effective area for signal transmission
Solution Approach 1:
The three-part electrode structure enables a manufacturing process that maintains efficiency while achieving superior integrity. Each part can be formed using standard processes, but the segmented approach prevents the void and dimple formation that plagues conventional single-step formation.
Solution Approach 2:
The patent employs parameter changes in the plating process, including multiple plating steps with different conditions for forming different electrode parts. This allows optimization of each formation step to prevent defects while maintaining overall manufacturing efficiency.
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
The solution improves the physical and electrical reliability of through electrodes by preventing voids and dimples, increasing the effective area for signal shielding and heat dissipation, and enhancing bonding between the insulating layer and the electrode.
Implementation Method 1
enhancing bonding between the insulating layer and the electrode
Implementation Method 2
preventing voids and dimples through a post-plating process
Data Source
AI summary
A circuit board according to an embodiment includes an insulating layer including an upper surface and a lower surface; and a through electrode passing through the upper and lower surfaces of the insulating layer, wherein the through electrode includes: a first electrode part disposed adjacent to the lower surface of the insulating layer and having a first inclination such that a width decreases toward the upper surface of the insulating layer; a second electrode part disposed on the first electrode part and having a second inclination such that a width increases toward the upper surface of the insulating layer; and a third electrode part disposed between the first electrode part and the second electrode part and having a third inclination different from the first and second inclinations; wherein a width of a portion of the first electrode part closest to the third electrode part is less than or equal to a width of the third electrode part, and wherein a width of a portion of the second electrode part closest to the third electrode part is smaller than or equal to a width of the third electrode part.