Printed Substrate Plating Film with Pi-Acceptor Molecules
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Solution Overview
Problem
Conventional printed substrates face soldering failures due to rapid depletion of pre-flux, leading to oxidation of lands when stored in air, which restricts their long-term use in electronic devices.
Innovation Solution
Incorporating a plating film with a metal as the main constituent and a pi-acceptor molecule, such as 2,2′-bipyridyl derivatives, dispersed at a content of at least 0.1 weight percent, which forms pi-backbonding with metal dangling bonds, thereby reducing oxidation without the need for pre-flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-flux is applied to the land surface to restrict oxidation, then oxidation resistance is improved, but the pre-flux depletes quickly when stored in air, leading to soldering failure
Solution Approach 1:
The patent changes the chemical composition parameters of the plating film by incorporating pi-acceptor molecules with specific ligand field splitting properties (equal to or greater than 2,2'-bipyridyl) at controlled concentrations (0.01-5 mass%). This modifies the electronic structure and oxidation resistance characteristics of the plating film, enabling long-term oxidation protection without pre-flux
Solution Approach 2:
The patent creates a composite plating film structure combining metal base material with dispersed pi-acceptor molecules. This composite structure leverages the synergistic effect between the metal matrix and the pi-acceptor molecules to achieve enhanced oxidation resistance and prolonged storage stability
2Adaptability or versatility
If the printed substrate is stored in air for long term, then manufacturing flexibility is improved, but oxidation of the land occurs due to pre-flux depletion
Solution Approach 1:
The plating film with pi-acceptor molecules provides self-protection against oxidation without requiring external pre-flux application. The inherent structure of the plating film actively prevents oxidation during storage, eliminating the need for separate protective measures and enabling reliable long-term storage in air
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 effectively restricts oxidation of the land for an extended period, even when stored in air, ensuring reliable soldering and enhancing the durability of electronic devices by maintaining solderability and heat resistance.
Implementation Method 1
the pi-acceptor molecule forms a pi-backbonding with a metal having the dangling bonds. The dangling bonds at the surface of the land are reduced or removed. As a result, oxidation of the land is restricted
Data Source
AI summary
A printed substrate includes a land that is to be soldered. The land includes a plating film that defines a surface of the land. The plating film includes a metal as a main constituent and a pi-acceptor molecule that is dispersed in the plating film. The pi-acceptor molecule has pi-acceptability and causes ligand field splitting equal to or greater than that of 2,2′-bipyridyl in spectrochemical series. A content of the pi-acceptor molecule in the plating film is equal to or greater than 0.1 weight percent, in terms of carbon atoms, with respect to the metal of the plating film.