PCB Hole Filling via Conductive Paste and Galvanic Metallization
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Solution Overview
Problem
Current methods for filling holes in printed circuit boards, such as galvanic metallization and resin-based fillings, face challenges with high costs, low thermal conductivity, low peel strength, and long processing times, especially in high current applications like electric vehicles where high reliability and efficiency are critical.
Innovation Solution
A hybrid process combining conductive metal powder paste and galvanic metallization, where the paste with metal powder and electrolyte is introduced into holes, and subsequent galvanic metallization deposits elemental metal, enhancing bonding and reducing processing time, without the need for fine-grained metal powders or complex systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If galvanic metallization is used to fill holes in PCBs, then electrical conductivity is improved, but process time increases significantly and filling completeness becomes problematic for large holes
Solution Approach 1:
The patent applies preliminary action by first forming a metal sleeve layer on the inner circumferential surface of holes through galvanic metallization before introducing the paste. This pre-prepared metallic structure provides immediate electrical conductivity pathways and serves as a foundation for subsequent metal powder deposition, reducing the time required for complete filling while ensuring conductivity.
Solution Approach 2:
The patent uses composite materials by combining metal powder (such as copper powder) with paste vehicle in a specific ratio within the paste composition. This composite structure allows the filling material to provide both electrical conductivity from the metal particles and proper adhesion/processability from the paste vehicle, achieving reliable electrical connection while maintaining manufacturability.
2Productivity
If resin-based filling material is used, then processing time is reduced and hole filling is simplified, but thermal conductivity and peel strength deteriorate
Solution Approach 1:
The patent employs composite materials by incorporating conductive metal particles (such as copper, silver, or aluminum powder) into the paste formulation. This composite structure provides thermal and electrical conductivity pathways through the metal particles while the paste matrix ensures proper adhesion and processing characteristics, thereby maintaining high productivity without sacrificing thermal performance.
Solution Approach 2:
The patent applies local quality by concentrating conductive metal particles specifically within the paste that fills the holes, rather than using uniform resin-based material throughout. This localized concentration of conductive phases in the critical heat dissipation and electrical connection zones enhances thermal and electrical conductivity where most needed, while maintaining the processing advantages of paste filling.
3Ease of manufacture
If resin-based filling with metal particles is used, then manufacturing complexity is reduced, but adhesion strength and thermal performance deteriorate
Solution Approach 1:
The patent applies preliminary action by forming a metal sleeve layer on the inner circumferential surface of holes before paste introduction. This pre-formed metallic structure provides superior adhesion substrates for the subsequent paste filling, ensuring strong mechanical bonding and high peel strength while maintaining manufacturing simplicity through the sequential process design.
Solution Approach 2:
The patent uses composite materials with conductive metal particles embedded in the paste matrix, where the metal particles enhance both thermal conductivity and mechanical strength. The combination of metal powder and paste vehicle creates a composite filling material that achieves high adhesion strength through metallic bonding while maintaining ease of manufacture through paste application methods.
4Manufacturing precision
If completely galvanic filling is used for small holes, then filling completeness is achieved, but process time becomes excessively long
Solution Approach 1:
The patent applies preliminary action by pre-forming a metal sleeve layer on the inner circumferential surface of holes through galvanic metallization before introducing the paste. This preliminary metallic structure ensures complete filling of the hole volume with conductive material, as the paste fills the remaining space efficiently, achieving 100% filling completeness while significantly reducing the overall process time compared to relying solely on slow galvanic deposition.
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 achieves high electrical and thermal conductivity, strong peel strength, and reduced processing time, making it suitable for various hole sizes and applications, including high-density interconnects in electric vehicles, with stable and cost-effective results.
Implementation Method 1
introducing a paste comprising an electrically conductive metal powder and an electrolyte into the at least one hole
Implementation Method 2
the paste with metal powder and electrolyte is introduced into holes, and subsequent galvanic metallization deposits elemental metal, enhancing bonding
Implementation Method 3
galvanic metallisation of the printed circuit board so that elemental metal is deposited from the electrolyte in the at least one hole during the galvanic metallisation
Implementation Method 4
elemental metal is deposited from the electrolyte in the at least one hole during the galvanic metallisation
Implementation Method 5
the electrolyte introduced with the paste (and possibly further electrolyte entering the filling from the electroplating bath) and the metal deposited therefrom bond the conductive material to each other and to the hole wall
Data Source
AI summary
Disclosed are a method for filling at least one hole formed in a printed circuit board, a printed circuit board filled in such a manner, and a vehicle having such a printed circuit board. The method of filling at least one hole formed in a printed circuit board comprises: introducing a paste comprising an electrically conductive metal powder and an electrolyte into the at least one hole of the printed circuit board, S1; and galvanic metallization of the printed circuit board so that elemental metal is deposited from the electrolyte in the at least one hole during the galvanic metallisation, S2.