Wiring Substrate Via Plating Thickness Control
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Solution Overview
Problem
Wiring substrates with varying via hole capacities and filled with different metal posts suffer from reliability issues due to height discrepancies, leading to connection failures and solder-related problems such as gaps or shorts.
Innovation Solution
The wiring substrate design includes a plurality of first wiring portions with an insulation layer and openings of varying capacities, where the via wiring is formed with an electroless plating structure that increases in thickness with the capacity of the opening, ensuring the electrolytic plated layers and metal posts have consistent heights across different openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If via holes of different capacities are filled with via wirings to accommodate varying electrical requirements, then the electrical performance and adaptability are improved, but the metal posts formed on the via wirings have different heights which decreases connection reliability
Solution Approach 1:
The patent applies local quality by varying the electroless plating structure thickness specifically in regions with larger opening capacities. The via wiring includes an electroless plating structure with N layers where N≥0, and the thickness increases as the opening capacity increases. This localized adjustment ensures that metal posts on all via wirings achieve substantially the same height, resolving the reliability issue while maintaining adaptability to different electrical requirements.
2Reliability
If the electroless plating structure thickness is increased in larger capacity openings to equalize metal post heights, then connection reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent employs parameter changes by systematically varying the electroless plating structure thickness based on opening capacity parameters. The via wiring includes an electroless plating structure with N layers where N≥0, and the thickness is adjusted as a controllable parameter according to the opening capacity. This approach allows precise control of metal post heights while maintaining a systematic and manageable manufacturing process.
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 configuration enhances the reliability of connections by aligning the upper surfaces of connection terminals with the same plane, reducing the likelihood of connection failures and solder-related issues, while allowing for miniaturization of the wiring layer.
Implementation Method 1
The via wiring includes an electrolytic plated layer and an electroless plating structure including N layers where N represents an integer greater than or equal to zero. The electroless plating structure is arranged between the electrolytic plated layer and the upper surface of a corresponding one of the first wiring portions exposed in a bottom of a corresponding one of the openings.
Data Source
AI summary
A wiring substrate includes first wiring portions, an insulation layer covering the first wiring portions, openings extending through the insulation layer in a thickness-wise direction, partially exposing upper surfaces of the first wiring portions, and differing from each other in capacity, and second wiring portions, each of which includes a via wiring filling one of the openings and a columnar connection terminal electrically connected to the via wiring and arranged on an upper surface of the insulation layer. The via wiring includes an electrolytic plated layer and an electroless plating structure including N layers (N is integer and ≥0) arranged between the electrolytic plated layer and the upper surface of the first wiring portion exposed in a bottom of the opening. The via wiring is formed so that the electroless plating structure has a thickness that increases as a capacity of the opening filled with the via wiring is increased.