Wiring Substrate Trench Slope and Segmented Plating
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Solution Overview
Problem
Existing wiring substrate manufacturing methods face issues with the generation of seams or voids at bonding parts between plating films, particularly in high aspect ratio trenches and penetration holes, leading to potential disconnection of conductive layers due to thermal stress, which affects connection reliability with external terminals.
Innovation Solution
The wiring substrate design incorporates a trench with a slope surface connecting the inner bottom and side surfaces, and a penetration hole with a recessed first conductive layer to prevent plating film growth from multiple directions, using a second conductive layer that covers the first conductive layer and trench, and a third conductive layer that fills the trench, thereby reducing the likelihood of seam or void formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plating films are grown in multiple directions to fill high aspect ratio trenches and penetration holes, then the conductive layers can be formed, but seams or voids are generated at bonding parts between plating films
Solution Approach 1:
The conductive layer formation is divided into multiple stages: first forming a bottom conductive layer, then forming a first conductive layer on specific surfaces, and finally forming a second conductive layer to complete the filling. This segmentation prevents plating films from growing in multiple directions simultaneously, eliminating seam and void formation at bonding parts.
Solution Approach 2:
The bottom conductive layer is formed in advance before forming the main conductive layers. This preliminary action provides a foundation that prevents subsequent plating films from growing in multiple directions, thereby preventing seam and void formation while ensuring complete filling of high aspect ratio trenches and penetration holes.
2Manufacturing precision
If plating films are grown from multiple directions, then high aspect ratio trenches can be filled, but thermal stress causes disconnection of conductive layers
Solution Approach 1:
The conductive layer formation is divided into multiple stages: first forming a bottom conductive layer, then forming a first conductive layer on specific surfaces, and finally forming a second conductive layer to complete the filling. This segmentation prevents plating films from growing in multiple directions simultaneously, eliminating seam and void formation at bonding parts.
Solution Approach 2:
The bottom conductive layer is formed in advance before forming the main conductive layers. This preliminary action provides a foundation that prevents subsequent plating films from growing in multiple directions, thereby preventing seam and void formation while ensuring complete filling of high aspect ratio trenches and penetration holes.
3Ease of manufacture
If conventional plating methods are used, then conductive layers can be formed, but seams or voids are generated affecting connection reliability
Solution Approach 1:
The conductive layer formation is divided into multiple stages: first forming a bottom conductive layer, then forming a first conductive layer on specific surfaces, and finally forming a second conductive layer to complete the filling. This segmentation prevents plating films from growing in multiple directions simultaneously, eliminating seam and void formation at bonding parts.
Solution Approach 2:
The first conductive layer is formed selectively on specific surfaces (inner bottom surface and/or inner side surface) rather than uniformly on all surfaces. This local quality approach ensures proper adhesion and prevents seam formation at bonding parts while maintaining ease of manufacture.
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 preventing seam or void generation, reducing the risk of conductive layer disconnection and improving thermal stress resistance, thus ensuring stable electrical connections.
Implementation Method 1
a first conductive layer filling at least a portion of the penetration hole and including a top surface toward the trench
Implementation Method 2
a second conductive layer covering the top surface of the first conductive layer and formed on at least a portion of the trench
Data Source
AI summary
A wiring substrate includes a body including first and second surfaces, a trench having an opening on the first surface and including, a bottom surface, a side surface, and a slope surface that connects a peripheral part of the bottom surface to a one end part of the side surface and widens from the peripheral part to the one end part, the one end part being an end part opposite from the first surface, a hole including an end communicating with the bottom surface and another end being open on the second surface, a first layer filling at least a portion of the hole and including a top surface toward the trench, a second layer covering the top surface and formed on at least a portion of the trench except for a part of the side surface, and a third layer covering the second layer and filling the trench.