Multilayer PCB Blind-Hole Plating Through a Connection Groove
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Solution Overview
Problem
Existing methods for forming blind holes in printed circuit boards are limited by insufficient depth and aspect ratio, particularly in thick multilayer boards, leading to ineffective electroplating and hindered high-speed signal transmission.
Innovation Solution
A method involving mechanical drilling and laser processing to form through and blind holes, with a connection groove, allowing electrolyte solution flow to create a conductive layer for electrical connection between layers, and filling the groove with a medium to enhance electroplating and signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional drilling methods are used to form blind holes in thick multilayer printed circuit boards, then the manufacturing process is simple, but the hole depth and aspect ratio are insufficient leading to ineffective electroplating
Solution Approach 1:
The drilling process is segmented into two distinct stages: first, a mechanical drill forms an initial hole to a predetermined depth; second, a laser processing device completes the blind hole formation from the first hole. This segmentation allows each device to operate within its optimal capability range, achieving the required depth and aspect ratio that neither device could achieve alone.
Solution Approach 2:
The mechanical drill acts as an intermediary that creates the initial hole structure, which then serves as the starting point for laser processing. This intermediate structure enables the laser to effectively complete the blind hole formation, bridging the gap between mechanical drilling limitations and laser processing capabilities.
2Adaptability or versatility
If the multilayer printed circuit board is made thicker to accommodate more wiring layers, then the functionality and signal transmission capability are improved, but the electroplating effectiveness deteriorates due to insufficient blind hole depth
Solution Approach 1:
The blind hole formation is segmented into mechanical drilling for the initial structure and laser processing for the final depth achievement. This allows the system to maintain effective electroplating in thick multilayer boards by ensuring adequate blind hole depth and aspect ratio, which would be impossible with traditional single-method drilling.
3Reliability
If a connection groove is formed between the through hole and blind hole, then the electrolyte solution flow path is established for electroplating, but additional drilling steps are required
Solution Approach 1:
The connection groove formation is merged with the blind hole drilling process. The mechanical drill and laser processing device work in sequence to create both the blind hole and the connection groove in a integrated operation, rather than as separate steps. This reduces the total number of drilling operations while ensuring proper electrolyte flow paths for electroplating.
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
Enables effective electroplating and high-speed signal transmission in multilayer printed circuit boards of varying thicknesses, improving practicality and connectivity.
Implementation Method 1
drilling a reflow hole in the multilayer printed circuit board using a mechanical drill
Implementation Method 2
drilling from the bottom surface of the first hole position to the upper surface of the wiring layer using laser
Implementation Method 3
allowing an electrolyte solution to flow through the through hole, the connection groove, and the blind hole to form a conductive layer
Data Source
AI summary
This application relates to a printed circuit board manufacturing method and a printed circuit board. The method includes: forming a through hole in a multilayer printed circuit board that runs through the multilayer circuit board, where the multilayer printed circuit board is provided with an upper printed circuit board, a wiring layer, and a lower printed circuit board that are stacked; forming a blind hole from the upper printed circuit board to the wiring layer in the multilayer circuit board; drilling between the through hole and the blind hole to form a connection groove, where the through hole is in communication with the blind hole through the connection groove; and allowing an electrolyte solution to flow through the through hole, the connection groove, and the blind hole to form a conductive layer, achieving an electrical connection between the upper printed circuit board and the lower printed circuit board.