Wiring Substrate Adhesion via Composite Resin Insulating Layer
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Solution Overview
Problem
Existing wiring substrates face challenges in achieving high-quality conductor formation and adhesion on glass substrates, particularly in maintaining flatness and preventing peeling due to thermal shocks and expansion differences between glass and resin insulating layers.
Innovation Solution
A wiring substrate design incorporating a glass substrate with through-hole conductors, a resin insulating layer containing inorganic particles, and a conductor layer formed by sputtering and electrolytic plating, ensuring strong adhesion and preventing peeling through the use of aluminum and silicon in the seed layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin insulating layer is formed on a glass substrate, then electrical insulation is achieved, but peeling occurs due to thermal shocks and expansion differences
Solution Approach 1:
The resin insulating layer is formed as a composite material containing inorganic particles (such as glass particles, alumina particles, or silica particles) dispersed within the resin matrix. This composite structure combines the adhesive properties of the resin with the thermal stability of the inorganic particles, allowing the layer to resist thermal shocks and expansion differences between the glass substrate and resin material, thereby preventing peeling while maintaining electrical insulation.
2Reliability
If conductor layers are formed on resin insulating layers, then electrical connectivity is achieved, but fine signal wiring formation becomes difficult
Solution Approach 1:
The resin insulating layer is designed with non-uniform inorganic particle distribution, creating local variations in surface properties. Specifically, the inorganic particles are distributed to form protrusions on the surface, which provide localized anchoring points for the conductor layer. This local quality enhancement ensures strong adhesion and reliable electrical connectivity at critical points while maintaining overall surface flatness necessary for fine signal wiring formation.
3Reliability
If inorganic particles are embedded in resin, then adhesion is improved, but surface flatness deteriorates
Solution Approach 1:
The inorganic particles are strategically distributed within the resin insulating layer to create localized protrusions rather than uniform surface coverage. These protrusions are confined to specific regions where adhesion is most critical (such as areas contacting the glass substrate or conductor layers), while maintaining overall surface flatness in other regions. This localized approach ensures strong adhesion where needed without compromising the ability to form fine signal wirings on flat surfaces.
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
The solution enables the formation of high-quality, fine signal wirings with improved adhesion and resistance to thermal shocks, reducing noise and ensuring reliable electrical connectivity.
Implementation Method 1
a conductor layer formed on a surface of the resin insulating layer and including a seed layer formed by sputtering
Implementation Method 2
an electrolytic plating layer formed on the seed layer
Data Source
AI summary
A wiring substrate includes a core substrate including a glass substrate and a through-hole conductor, a resin insulating layer having an opening extending through the resin insulating layer, a conductor layer including a seed layer and an electrolytic plating layer on the seed layer, and a via conductor formed in the opening such that the via conductor electrically connects to the through-hole conductor in the core substrate and includes the seed layer and electrolytic plating layer extending from the conductor layer. The resin insulating layer includes resin and inorganic particles including first and second particles such that the first particles are partially embedded in the resin and that the second particles are embedded in the resin, the first particles have first portions protruding from the resin and second portions embedded in the resin respectively, the surface includes the resin and exposed surfaces of the first portions exposed from the resin.