PCB Through-Hole Segmentation for Void Prevention
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Solution Overview
Problem
The increasing size and complexity of flip-chip ball grid array (FCBGA) substrates, particularly in 2.5D package products, lead to voids and unfilled areas in through-holes, which can cause reliability issues and signal transmission problems.
Innovation Solution
A printed circuit board design featuring a thick core with plugs disposed in through-holes using a bridge plating technique, where the through-holes are divided into areas by a first plating layer, and additional plugs are placed in these areas, increasing the plating area and preventing voids.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the substrate size is increased to accommodate more I/O and memories in 2.5D package products, then the functional capacity is improved, but voids may occur in the through-holes
Solution Approach 1:
The through-hole is divided into multiple sections by inserting a plug material that segments the hole into upper and lower portions. This segmentation allows for controlled filling and reduces void formation while maintaining the structural integrity needed for larger substrate designs.
Solution Approach 2:
A plating layer is formed in the through-hole before inserting the plug material. This preliminary plating action creates a foundation that facilitates complete filling and prevents voids, ensuring reliable signal transmission in the enlarged substrate structure.
2Ease of manufacture
If a conventional plugging process is used, then the process is simple, but voids and unfilled areas are generated in the through-hole
Solution Approach 1:
The through-hole filling process is segmented into distinct stages: first forming a plating layer, then inserting plug material. This segmentation ensures complete filling without voids while maintaining manufacturing efficiency through a systematic approach.
Solution Approach 2:
The plating layer is formed as a preliminary action before plug insertion. This preparatory step creates a receptive surface that ensures complete filling and eliminates voids, achieving high manufacturing precision without significantly complicating the overall process.
3Reliability
If the plating area in the through-hole is increased to improve signal transmission reliability, then the reliability is improved, but the plugging process becomes more complex
Solution Approach 1:
The through-hole structure is segmented into a plating layer region and a plug material region. This segmentation increases the effective plating area for signal transmission while keeping the process manageable by clearly defining separate functional zones.
Solution Approach 2:
The plating layer is formed as a preliminary action that simultaneously serves dual purposes: it increases the plating area for improved signal reliability and creates a foundation for subsequent plug insertion, thereby avoiding additional process complexity.
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 design effectively prevents voids and unfilled areas, enhances signal transmission reliability, and simplifies the plugging process by reducing the area to be filled, thereby improving yield and productivity.
Implementation Method 1
a first plating layer disposed in the through-hole to divide the through-hole into first and second areas
Implementation Method 2
a plug disposed in the through-hole
Data Source
AI summary
A printed circuit board includes: an insulating layer having one surface and the other surface; metal layers respectively disposed on the one surface and the other surface of the insulating layer; a through-hole penetrating through the insulating layer and the metal layers; a first plating layer disposed in a center portion of the through-hole in a thickness direction thereof; and a plug disposed in the through-hole.