Dynamic Plating Angle for Void-Free PCB Through Hole Filling
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Solution Overview
Problem
Conventional methods for filling through holes in multilayer printed circuit boards with metal to improve heat dissipation capacity often result in voids and seams, which can lead to thermal shock and degradation of electrical characteristics, especially when the aspect ratio of the holes is high.
Innovation Solution
A plating method that involves spraying a plating solution at a non-perpendicular angle to the printed board, changing the spray angle during the plating process, and adjusting the board's posture, while using a copper sulfate plating solution, to ensure precise metal filling without voids or seams, even in holes with increased aspect ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the through hole is filled with metal by plating to improve heat dissipation capacity, then the heat dissipation capacity is improved, but voids and seams are easily generated in the precipitated metal
Solution Approach 1:
The patent applies dynamics by changing the spray angle of the plating solution during the plating process. The spray angle is dynamically adjusted from an initial angle (e.g., 30-60 degrees from perpendicular) to a final angle (e.g., 0-30 degrees from perpendicular) at a predetermined time point during plating. This dynamic change in spraying conditions prevents voids and seams while maintaining heat dissipation improvement.
Solution Approach 2:
The patent changes physical parameters of the plating process, specifically the spray angle parameter. By changing the spray angle from a larger initial angle to a smaller final angle during plating, the patent achieves complete filling without voids or seams. This parameter change approach directly resolves the contradiction between heat dissipation improvement and manufacturing precision.
2Productivity
If the aspect ratio of the through hole is increased to improve degree of integration, then the degree of integration is increased, but voids and seams are more likely to occur in the metal filling
Solution Approach 1:
The patent uses dynamic adjustment of spray angle to handle high aspect ratio through holes. By changing the spray angle during plating, the patent ensures that even in high aspect ratio holes (where voids and seams are more likely), the metal fills completely without defects, thus maintaining both high integration and manufacturing precision.
Solution Approach 2:
The patent performs preliminary action by setting an initial spray angle that is larger than the final angle. This preliminary larger angle helps in initial metal deposition and prevents void formation early in the process, especially important for high aspect ratio holes where voids are more likely to occur.
3Device complexity
If conventional plating methods are used to fill through holes, then the plating process is simple, but the plating time is extended and voids or seams occur
Solution Approach 1:
The patent introduces dynamic spray angle adjustment to achieve faster and defect-free plating. Although this adds some process complexity, it significantly reduces plating time by preventing void and seam formation that would require rework or extended plating time, thus netting a time reduction.
Solution Approach 2:
The patent applies periodic action by dividing the plating process into two stages with different spray angles. The first stage uses a larger spray angle for initial deposition, and the second stage uses a smaller spray angle for final filling. This periodic change in spraying conditions accelerates the process while preventing defects.
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 allows for precise metal filling of through holes, enhancing the heat dissipation and reliability of printed boards while reducing the occurrence of voids and seams, and completing the process in a shorter time than conventional methods.
Implementation Method 1
filling a through hole of a printed board with a metal by electroless plating or electroplating
Implementation Method 2
filling a through hole of a printed board with a metal by electroless plating or electroplating
Implementation Method 3
air bubbles are sprayed onto the printed board in the plating solution
Data Source
AI summary
The invention eliminates defects generated in a metal filling a through hole of a printed board by changing an angle at which a plating solution is sprayed or by changing a posture of the printed board at a time point in a process of precipitating the metal from the plating solution and filling the through hole with the precipitated metal while the plating solution or air bubbles are being sprayed onto the printed board.