Through Wiring Substrate Catalyst Removal
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Solution Overview
Problem
Conventional through wiring substrates experience short circuits in the gaps between wiring structures during non-electrolytic plating processes, such as Ni/Au plating, due to inadequate removal of catalyst metal particles.
Innovation Solution
Incorporating a substrate with a pair of principal surfaces and a through hole, a through electrode, a first and second wiring layer, an underlying metal layer, and catalyst metal particles between the underlying metal layer and the wiring layers, which are effectively removed during patterning, preventing non-electrolytic plating deposition in the gaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If non-electrolytic plating is performed on the surfaces of the wiring structures, then the wiring structures are formed, but short circuits arise in the gaps between wiring structures due to catalyst metal particles remaining on the substrate surface
Solution Approach 1:
The patent extracts and removes catalyst metal particles from the substrate surface through wet etching using a specific etching solution before performing non-electrolytic plating. This extraction process eliminates the harmful catalyst particles that would otherwise cause unwanted plating deposition in gap areas, preventing short circuits while maintaining wiring structure formation capability
Solution Approach 2:
The patent applies preliminary action by performing wet etching to remove catalyst metal particles from the substrate surface before the non-electrolytic plating process. This preliminary removal of catalyst particles prevents them from catalyzing unwanted plating reactions in the gap areas, thereby preventing short circuits before they can occur
2Manufacturing precision
If the underlying metal layer is removed by wet etching to expose the substrate surface, then the substrate surface is exposed for plating, but catalyst metal particles may remain in the exposed part causing plating deposition in gaps
Solution Approach 1:
The patent extracts catalyst metal particles from the exposed substrate surface using a specifically formulated wet etching solution that selectively removes the particles while leaving the underlying metal layer intact in wiring areas, preventing particle contamination in gap regions
Solution Approach 2:
The patent changes the chemical parameters of the etching solution to achieve selective removal of catalyst metal particles. By adjusting the composition and properties of the wet etching solution, the process selectively targets and removes catalyst particles while preserving the underlying metal layer structure
3Ease of manufacture
If catalyst metal particles are present between the underlying metal layer and wiring layer, then non-electrolytic plating can be performed, but particles remain after patterning causing short circuits
Solution Approach 1:
The patent extracts catalyst metal particles from between the underlying metal layer and wiring layer through selective wet etching. This extraction maintains the non-electrolytic plating capability by preserving the underlying metal layer while removing harmful particles that would cause short circuits
Solution Approach 2:
The patent uses an intermediary wet etching process between the underlying metal layer formation and wiring layer deposition. This intermediary step selectively removes catalyst particles while leaving the underlying metal layer intact, serving as a mediating process that preserves plating capability while eliminating short circuit risks
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 prevents short circuits and enhances adhesion between the substrate and wiring layers, allowing for high-density and downsized through wiring substrates with reduced risk of electroplating deposition in exposed areas.
Implementation Method 1
the catalyst metal particles are sufficiently removed along with the underlying metal layer when removing the underlying metal layer by wet etching in patterning
Implementation Method 2
catalyst metal particles existing between the underlying metal layer and the first wiring layer and between the through electrode and the inner surface of the through hole
Implementation Method 3
a through electrode provided on the inner surface of the through hole; a first wiring layer provided on one of the principal surfaces and connected to the through electrode; a second wiring layer provided on the other of the principal surfaces and connected to the through electrode
Data Source
AI summary
A through wiring substrate comprises a substrate having a pair of principal surfaces and a through hole penetrating between the pair of principal surfaces, the pair of principal surfaces and an inner surface of the through hole being electrically insulative; a through electrode provided on the inner surface of the through hole; a first wiring layer provided on one of the principal surfaces and connected to the through electrode; a second wiring layer provided on the other of the principal surfaces and connected to the through electrode; an underlying metal layer provided between the one of the principal surfaces and the first wiring layer; and catalyst metal particles existing between the underlying metal layer and the first wiring layer and between the through electrode and the inner surface of the through hole.