Optical Wiring Substrate Layout for Thermal Alignment Stability

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Solution Overview

Problem

Existing wiring substrates face challenges in efficiently positioning and maintaining optical waveguides due to thermal expansion mismatch between the waveguide and the support substrate, leading to misalignment and reduced optical coupling efficiency with optical components and fibers.

Innovation Solution

The wiring substrate incorporates a support substrate with a lower thermal expansion coefficient than the optical waveguide, allowing the waveguide to be formed in a non-conductor region, with penetrating conductors connecting the optical and electrical components, ensuring precise positioning and alignment despite temperature changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a support substrate with the same thermal expansion coefficient as the optical waveguide is used, then manufacturing is simpler, but thermal expansion mismatch causes misalignment and reduced optical coupling efficiency

Engineering Contradiction:

Improveoptical coupling efficiencyVSAvoidsubstrate structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The support substrate is divided into a conductor region and a non-conductor region with different material properties. The non-conductor region has a lower thermal expansion coefficient than the optical waveguide to match and maintain alignment, while the conductor region provides electrical connectivity. This local differentiation resolves the contradiction by providing both alignment stability and electrical functionality without requiring a completely complex multi-substrate structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The support substrate uses composite material construction with regions having different thermal expansion coefficients. By combining materials with appropriate thermal expansion properties in specific regions, the substrate achieves both mechanical support for alignment stability and electrical conductivity where needed, resolving the contradiction between simplicity and performance.

Inventive Principle:

Principle #40Composite materials

2Manufacturing precision

If the optical waveguide is formed directly on the support substrate without region differentiation, then manufacturing is easier, but positioning and alignment of optical components becomes imprecise

Engineering Contradiction:

Improvewaveguide positioning precisionVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Reliability

If penetrating conductors are not used, then the structure is simpler, but electrical connections between optical and electrical components become unreliable

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidconductor structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The support substrate merges multiple functions into a single component: it provides mechanical support for the optical waveguide, enables precise positioning through thermal expansion matching in the non-conductor region, and provides electrical connectivity through penetrating conductors in the conductor region. This integration resolves the contradiction by combining structural and electrical functions in one element rather than requiring separate components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The support substrate serves multiple functions simultaneously: mechanical support, thermal expansion compensation for alignment, and electrical connectivity through penetrating conductors. This multi-functionality resolves the contradiction by making a single component perform multiple roles, reducing overall system complexity while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 design enhances optical coupling efficiency by minimizing misalignment and facilitating reliable electrical and mechanical connections between optical components and the electrical wiring part, improving overall performance.

Implementation Method 1

The support substrate has a thermal expansion coefficient lower than a thermal expansion coefficient of the optical waveguide

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

an optical waveguide including a core part and a cladding part

Methodology Applied

Scientific EffectOptical waveguide: Waveguide (optics)

Data Source

PatentUS20250216614A1Wiring substrate

Publication Date: 2025.07.03 IBIDEN CO LTD

AI summary

A wiring substrate includes an electrical wiring part including insulating layers and conductor layers, and an optical wiring part positioned on a surface of the electrical wiring part and including a support substrate and an optical waveguide such that the optical wiring part has a component region configured to position a component on the optical wiring part and the optical waveguide includes a core part and a cladding part. The support substrate in the optical wiring part has a thermal expansion coefficient lower than a thermal expansion coefficient of the optical waveguide and includes a conductor region and a non-conductor region such that the optical waveguide is formed on a surface of the support substrate in the non-conductor region and the optical wiring part includes one or more penetrating conductors penetrating through the support substrate in the conductor region.