Conductive Paste Wiring Layer Embedding for Narrow-Gap Substrates
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Solution Overview
Problem
Existing wiring substrates with copper nanoparticles face challenges in reducing the gap between adjacent wiring layers due to poor adhesion and spreading of nanoparticles, leading to potential short circuits and difficulty in embedding particles in the base body.
Innovation Solution
A conductive paste comprising metal nanoparticles and metal particles with a specific size range is used, which is applied to an insulating base body and heated and pressurized to form a wiring layer, embedding part of the layer in the base body, thereby improving adhesion and reducing lateral spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper nanoparticles are used in the wiring layer, then the conductivity is improved, but the gap between adjacent wiring layers increases due to particle spreading
Solution Approach 1:
The patent uses a composite particle system combining copper nanoparticles (1-100 nm) for conductivity with copper fine particles (1-10 μm) for structural stability. This composite approach allows the nanoparticle component to provide excellent electrical conductivity while the fine particle component restricts lateral spreading, thereby maintaining small gaps between adjacent wiring layers.
Solution Approach 2:
The patent optimizes the particle size distribution parameters by specifying copper nanoparticles with median diameter of 1-100 nm and copper fine particles with median diameter of 1-10 μm. By controlling these size parameters and their ratio (5-95 mass% nanoparticles), the invention achieves both high conductivity and minimal spreading.
2Reliability
If copper nanoparticles are used in the wiring layer, then the conductivity is improved, but the adhesion to the base body deteriorates
Solution Approach 1:
The patent creates a composite particle structure where copper nanoparticles provide conductivity while copper fine particles enhance adhesion to the base body. The fine particles act as anchors that bond more effectively to the substrate, while the nanoparticle component ensures excellent electrical properties, thus resolving the adhesion-conductivity trade-off.
Solution Approach 2:
The invention applies different particle sizes at different functional locations: copper fine particles (1-10 μm) near the base body interface provide strong adhesion, while copper nanoparticles (1-100 nm) in the upper wiring layer provide high conductivity. This spatial differentiation of particle functions simultaneously achieves both goals.
3Productivity
If the gap between wiring layers is reduced, then the integration density is improved, but the risk of short circuits increases due to particle spreading
Solution Approach 1:
The patent employs a composite particle system where copper fine particles (1-10 μm) act as spacing maintainers that prevent excessive lateral spreading, while copper nanoparticles (1-100 nm) ensure conductivity. This allows aggressive gap reduction for high integration density while the fine particle framework prevents short circuits by maintaining particle separation.
Solution Approach 2:
By optimizing the particle size ratio parameter (5-95 mass% nanoparticles) and the size distribution parameters (nanoparticle median diameter 1-100 nm, fine particle median diameter 1-10 μm), the invention enables tight wiring spacing without short circuits, achieving high integration density with maintained reliability.
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 method effectively reduces the gap between wiring layers, enhances adhesion between the wiring layer and the base body, and prevents short circuits by embedding part of the wiring layer in the base body, improving the manufacturing process for light-emitting devices.
Implementation Method 1
forming a wiring layer by heating and pressurizing the conductive paste by using a roll press or a hard SUS plate
Implementation Method 2
the conductive paste is heated and pressurized such that part of the wiring layer in a thickness direction is embedded in at least the first surface of the insulating base body
Data Source
AI summary
A method of manufacturing a wiring substrate includes providing a conductive paste including metal nanoparticles, metal particles, and a resin, disposing the conductive paste on at least a first surface of an insulating base body, and forming a wiring layer by heating and pressurizing the conductive paste by using a roll press or a hard SUS plate. In the providing the conductive paste, the ratio of a mass of the metal nanoparticles to the total mass of the metal nanoparticles and the metal particles is in a range of 5 mass % to 95 mass %, and the conductive paste is heated and pressurized such that part of the wiring layer in a thickness direction is embedded in at least the first surface of the insulating base body.