Flexible PCB Conductive Pillars for High-Density Pad Distribution
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Solution Overview
Problem
The increasing density of electronic product components requires a flexible printed circuit board with enhanced pad distribution and connectivity, which existing technologies struggle to achieve effectively.
Innovation Solution
A method for forming a flexible printed circuit board involving a substrate with conductive pattern layers, through holes, and conductive pillars, where the pillars are formed by electroplating and exposed to create electrical contact pads, with optional stiffening and grooves for improved structural integrity and connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the pad distribution density is increased to meet miniaturization requirements, then the connectivity and electrical connection efficiency are improved, but the structural integrity and manufacturing complexity increase
Solution Approach 1:
The patent transitions from planar pad distribution to three-dimensional vertical stacking by forming conductive pillars through electroplating that extend vertically from the substrate. This dimensional change allows multiple pads to be stacked in the vertical direction, increasing pad density without proportionally increasing lateral structural complexity
Solution Approach 2:
The patent implements nested structures where conductive pillars are formed within through-holes of the substrate, and stiffeners are embedded within grooves on the substrate surface. This nesting approach consolidates multiple functional elements into compact configurations, increasing pad density while managing structural complexity
2Reliability
If electroplating is used to form conductive pillars for high-density pad distribution, then electrical connectivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent performs preliminary actions by forming through-holes and applying conductive seed layers before electroplating the conductive pillars. This preliminary preparation ensures proper alignment and conductivity pathways are established before the critical electroplating process, reducing precision requirements during pillar formation
Solution Approach 2:
The patent utilizes parameter changes in the electroplating process, including controlling current density, plating time, and electrolyte composition, to achieve precise pillar dimensions and electrical properties. By optimizing these parameters, the process achieves high electrical connectivity while maintaining manufacturability
3Strength
If stiffeners and grooves are added to improve structural integrity, then mechanical strength is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by placing stiffeners specifically within grooves at critical locations on the substrate where mechanical support is needed, rather than uniformly across the entire structure. This localized approach provides necessary structural integrity while minimizing overall device complexity
Solution Approach 2:
The patent merges multiple functions into integrated structures: grooves serve both as mechanical features for stiffener attachment and as alignment features for pad positioning. This merging of functions reduces the number of separate components needed, improving structural integrity while controlling device 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 approach increases the density and efficiency of electrical connections, enabling better support for high-density electronic components while maintaining flexibility, thus addressing the challenge of miniaturization in electronic products.
Implementation Method 1
conductive pillars, where the pillars are formed by electroplating
Data Source
AI summary
A method for manufacturing a flexible printed circuit board, comprising: providing a flexible printed circuit substrate; defining first through holes and second through holes through the flexible printed circuit substrate; and forming first conductive pillars and second conductive pillars; and defining first grooves by removing a portion of each first conductive pillar and defining second grooves by removing a portion of each second conductive pillar; the first grooves and the second grooves are defined from an outer surface of the flexible printed circuit board on the second conductive pattern layer side to a surface of the second conductive pattern layer away from the first conductive pattern layer; each of the first grooves is aligned with and corresponds to one first conductive pillar, and each of the second grooves is aligned with and corresponds to one second conductive pillar.