Boron Intermediary Layer for Stable Metal Plating in Through Holes
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Solution Overview
Problem
Reliably achieving electrical connection in through-wiring patterns within semiconductor devices is challenging due to difficulties in forming metal layers on the inner surfaces of through holes, especially when these surfaces are aligned with the thickness direction or intersecting it, and in fine holes.
Innovation Solution
A wiring structural body is created with a silicon substrate having through holes, an insulating layer, a boron layer on the insulating layer, and a metal layer formed on the boron layer by plating, which stabilizes the metal layer formation regardless of the inner surface orientation or hole shape, ensuring reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a metal layer is formed directly on the insulating layer on the inner surface of the through hole by vapor deposition, then the formation process is simple, but the metal layer cannot be stably formed when the inner surface is along the thickness direction or intersects it
Solution Approach 1:
A boron layer is introduced as an intermediary between the insulating layer and the metal layer. The boron layer serves as a buffer that enables stable metal layer formation on the inner surface of the through hole, regardless of the surface orientation (whether along the thickness direction or intersecting it). This intermediary layer resolves the contradiction by allowing vapor deposition to proceed effectively while ensuring reliable electrical connection.
2Shape
If the inner surface of the through hole is oriented along the thickness direction or intersects it, then the through hole geometry is achieved, but vapor deposition cannot form the metal layer on these surfaces
Solution Approach 1:
The boron layer acts as a mediator that enables metal layer formation on surfaces with challenging orientations. By depositing the boron layer first, the system creates a surface that is conducive to subsequent metal layer formation via vapor deposition, even when the underlying through hole inner surface has orientations (along thickness direction or intersecting) that would normally prevent effective metal layer formation.
3Length of moving object
If the through hole width is reduced to 10-100 μm for fine wiring, then the wiring density is improved, but the electrical connection reliability becomes difficult to achieve
Solution Approach 1:
In fine through holes (10-100 μm width), the boron layer serves as a critical intermediary that ensures reliable electrical connection. The boron layer compensates for the challenges of forming metal layers in narrow spaces, providing a stable interface between the insulating layer and the metal layer, thereby maintaining connection reliability even when the through hole width is reduced for higher wiring density.
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 allows for stable and reliable electrical connections in through-wiring patterns, even in challenging geometries and fine holes, facilitating the production of interposers and semiconductor devices with improved connectivity.
Implementation Method 1
a boron layer provided on the insulating layer along the wiring pattern
Implementation Method 2
a metal layer provided on the boron layer
Data Source
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AI summary
Provided is a wiring structural body provided with a wiring pattern including a through-wiring pattern, the wiring structural body including: a silicon substrate having a through hole in which the through-wiring pattern is disposed; an insulating layer provided on a surface of the silicon substrate including an inner surface of the through hole along at least the wiring pattern; a boron layer provided on the insulating layer along the wiring pattern; and a metal layer provided on the boron layer.