Multilayer Substrate Flatness via Dummy Conductor Support
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Solution Overview
Problem
Conventional multilayer substrates with conductor patterns face challenges in maintaining flatness, especially when the conductor pattern has a winding shape, as island-shaped portions connected to thickness adjustment base material layers can deform, making it difficult to stack multiple insulating base material layers effectively.
Innovation Solution
Incorporating a dummy conductor on the thickness adjustment base material layer, which is electrically isolated from the conductor pattern, and designing the base material omitted portion to overlap with the conductor pattern, ensuring the conductor pattern is positioned within the base material omitted area, thereby stabilizing the island-shaped portion and reducing deformation during stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a thickness adjustment base material layer with an opening portion is used to ensure flatness, then the flatness of the multilayer substrate is improved, but the island-shaped portion inside the opening portion becomes easy to deform
Solution Approach 1:
The dummy conductor is formed on the thickness adjustment base material layer before stacking the insulating base material layers. This preliminary placement of the dummy conductor in the opening portion provides pre-support to the island-shaped portion, preventing deformation during the stacking process while maintaining the flatness achieved by the thickness adjustment layer.
Solution Approach 2:
The dummy conductor acts as an intermediary element between the opening portion and the island-shaped portion. It provides mechanical support to the island-shaped portion without being electrically connected to the conductor pattern, thus preventing deformation while maintaining electrical isolation.
2Shape
If the base material omitted portion is designed to overlap with the conductor pattern, then the flatness is improved and stacking is facilitated, but the complexity of the design increases
Solution Approach 1:
The base material omitted portion serves multiple functions: it provides thickness adjustment for flatness, defines the position of the dummy conductor, and ensures proper alignment with the conductor pattern during stacking. This multi-functionality reduces the need for separate design elements, thereby managing complexity while achieving multiple objectives.
3Shape
If the dummy conductor is electrically isolated from the conductor pattern, then the flatness and stacking stability are improved, but the electrical connectivity options are reduced
Solution Approach 1:
The dummy conductor is extracted from the electrical circuit function and dedicated solely to mechanical support. By separating the electrical connectivity function (handled by the conductor pattern) from the mechanical support function (handled by the dummy conductor), the design achieves flatness and stacking stability while maintaining electrical isolation.
Data Source
AI summary
A multilayer substrate includes a stacked body of insulating base material layers and conductor patterns on the insulating base material layers. A thickness adjustment base material layer includes a frame portion, an opening portion inside the frame portion, and an island shaped portion inside the frame portion, and connection portions to connect the island shaped portion to the frame portion. The conductor patterns, in a stacking direction of the insulating base material layers, are wound around the island shaped portion. A line width of the connection portions is smaller than the width of the island shaped portion connected to the frame portion through the connection portions. An area overlapped with the conductor patterns is larger in the opening portion than in the frame portion and the island shaped portion.