Wiring Substrate Optical Waveguide Protruding Core
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Solution Overview
Problem
Existing optical component mounting substrates face challenges in achieving high optical coupling efficiency and reliable electrical connections due to the interference of clad layers between optical waveguides and components, leading to suboptimal light transmission and connection quality.
Innovation Solution
A wiring substrate design featuring an insulating layer with a conductor pad, a covering layer, an optical waveguide with a core part that exposes its end surface beyond the insulating layer, and conductor posts made of plating metal that penetrate the covering layer for improved optical coupling and electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the optical waveguide is covered by a clad layer on the substrate side, then the optical waveguide is protected and integrated into the substrate, but the optical coupling efficiency with components is reduced due to interference from the clad layer
Solution Approach 1:
The patent extracts the core part of the optical waveguide from the substrate surface by forming it to protrude beyond the insulating layer. This extraction allows the light-emitting or light-receiving end to be positioned closer to components, improving optical coupling efficiency while removing the detrimental effect of the clad layer interference at the coupling interface.
Solution Approach 2:
The patent transitions from a planar integration approach to a three-dimensional structure by forming the core part to protrude vertically from the substrate surface. This dimensional change enables the optical waveguide to extend into the space above the substrate, facilitating better optical coupling with components mounted on the substrate without being constrained by the clad layer.
2Reliability
If conductor posts are formed to penetrate the covering layer for electrical connection, then electrical connectivity is improved, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The conductor posts serve multiple functions: they provide electrical connection between the conductor pad and components, act as mechanical support structures, and define the component mounting positions. This multi-functionality reduces the need for additional separate structures, thereby improving electrical connectivity without proportionally increasing overall structural complexity.
Solution Approach 2:
The conductor posts are formed in advance during substrate fabrication, penetrating through the insulating layer before components are mounted. This preliminary action ensures that electrical connection pathways are pre-established, simplifying the subsequent component mounting process and improving connection reliability without requiring complex post-assembly operations.
3Reliability
If the core part protrudes beyond the insulating layer surface, then optical coupling efficiency is enhanced, but the manufacturing precision requirements increase
Solution Approach 1:
The core part is formed to protrude from the insulating layer during the substrate fabrication process, before component mounting. This preliminary formation establishes precise positioning references that guide subsequent component placement, ensuring that the light-emitting or light-receiving ends align correctly with components while maintaining manufacturing feasibility.
Solution Approach 2:
The protruding core part structure serves as its own positioning reference and alignment guide. The geometry and position of the protruding core inherently define the optical coupling interface, eliminating the need for additional complex alignment mechanisms or precision adjustment features, thereby reducing overall manufacturing precision requirements while maintaining effective optical coupling.
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
Enhances optical coupling efficiency between the optical waveguide and components, while ensuring reliable electrical connections by minimizing interference from the clad layer and allowing for denser component mounting with better high-frequency characteristics.
Implementation Method 1
an optical waveguide that is provided on the surface and includes a core part that transmits light
Implementation Method 2
a conductor post that is formed of plating metal on the first conductor pad and penetrates the covering layer
Data Source
AI summary
A wiring substrate includes an insulating layer, a conductor layer formed on a surface of the insulating layer and including a conductor pad, a covering layer formed on the insulating layer and covering a portion of the insulating layer, an optical waveguide positioned on the surface of the insulating layer and including a core part, and a conductor post including plating metal and formed on the conductor pad such that the conductor post is penetrating through the covering layer and connected to a component. The insulating layer has a component region covered by the component when the component is connected to the conductor post, the core part has an end surface facing the opposite direction with respect to the insulating layer and exposed in the component region and a distance between the end surface and the surface of the insulating layer is greater than a thickness of the covering layer.