Coil Component Via Conductor Design for Plating Uniformity
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Solution Overview
Problem
In thin film power inductors, overplating issues occur due to via pads with greater widths than coil patterns, leading to plating thickness dispersion and increased DC resistance, which affects the stability and efficiency of high-frequency power supply in mobile devices.
Innovation Solution
The design omits via pads on the innermost peripheral portions of conductive patterns and forms a via conductor that fills only a portion of the via hole, ensuring the via conductor's diameter matches or exceeds the line width of the conductive patterns, thereby increasing contact areas and preventing overplating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If via pads with greater widths than coil patterns are formed, then alignment between via and coil is secured, but plating thickness dispersion occurs and DC resistance increases
Solution Approach 1:
The invention extracts and removes the via pad structure from the coil pattern, allowing the via to be directly formed on the coil pattern without an intermediate via pad layer, thereby eliminating the width mismatch that causes overplating
Solution Approach 2:
Instead of making the via pad larger than the coil pattern (conventional approach), the invention inverts the approach by making the via diameter equal to or larger than the coil pattern line width, eliminating the need for via pads and preventing overplating
2Manufacturing precision
If via pads greater than line widths of coil patterns are formed, then alignment is secured, but overplating occurs leading to increased DC resistance
Solution Approach 1:
The via pad structure is completely removed from the design, eliminating the source of overplating while maintaining alignment through direct via formation on the coil pattern
Solution Approach 2:
The via diameter parameter is changed to be equal to or larger than the coil pattern line width, which prevents overplating by eliminating the width differential that causes excessive plating material deposition
3Reliability
If via conductor fills entire via hole, then electrical connection is ensured, but plating thickness uniformity deteriorates due to overplating
Solution Approach 1:
The via diameter is increased to match or exceed the coil pattern line width, which changes the plating geometry to prevent overplating and achieve uniform plating thickness while maintaining adequate electrical connection
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 suppresses plating thickness dispersion, ensures uniformity, and improves DC resistance characteristics by enhancing electrical connectivity between layers, thus stabilizing power supply in high-frequency applications.
Implementation Method 1
a via conductor filling a portion of the via hole and connecting the innermost end portions of the first and second conductive patterns to each other
Data Source
AI summary
A coil component includes: a body portion; a coil portion; and an electrode portion, wherein the coil portion includes: a support member; a first coil layer disposed on a first surface of the support member, having first conductive patterns having a planar coil shape, and having a constant line width up to an innermost end portion; a second coil layer disposed on a second surface of the support member, having second conductive patterns having a planar coil shape, and having a constant line width up to an innermost end portion; a via hole penetrating through the support member and partially overlapping innermost end portions of the first and second conductive patterns; and a via conductor filling a portion of the via hole and connected to the innermost end portions of the first and second conductive patterns.