Hybrid PCB with Embedded High Density Circuit Regions
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Solution Overview
Problem
Traditional printed circuit board (PCB) technologies face challenges in achieving high density circuitry due to limitations in feature size, line spacing, and reliability issues such as taper, carbon contamination, and layer-to-layer shorting, especially when trying to create fine line or blind and buried vias, which increases costs and reduces reliability.
Innovation Solution
The method combines processes from printed circuit and semiconductor packaging industries to create high density circuit regions with fine line and feature pitches by using liquid dielectric materials, electro-less copper deposition, and electroplating to form conductive structures, allowing for the creation of small, low resistance vias and enabling the integration of active and passive components directly on the PCB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional laser ablation is used to create fine line or blind and buried vias, then via structures can be created, but significant taper, carbon contamination, layer-to-layer shorting, and high resistance interconnections occur
Solution Approach 1:
The patent replaces the mechanical laser ablation process with an electrochemical deposition process. Instead of using laser energy to ablate material and create vias, the invention uses electro-less copper deposition followed by electroplating to grow conductive structures directly on the circuit board. This substitution eliminates the harmful effects of laser processing (taper, carbon contamination, shorting) while achieving precise via structures with controlled geometry and low resistance.
Solution Approach 2:
The patent changes the fundamental parameters of the via creation process by transitioning from a subtractive laser ablation method to an additive electrochemical deposition method. The process parameters shift from laser power, pulse duration, and ablation rate to deposition chemistry, current density, and plating time. This parameter transformation enables precise control of via dimensions and electrical properties without the defects associated with laser processing.
2Productivity
If high density circuitry is attempted with reduced feature size and line spacing, then circuit density increases, but manufacturing complexity and costs increase
Solution Approach 1:
The patent segments the manufacturing process into distinct electrochemical deposition stages (electro-less copper deposition, electroplating, and optional additional plating layers). Each stage performs a specific function: initial via formation, via filling, and trace reinforcement. This segmentation allows for precise control of each process step, enabling high density circuitry to be manufactured with reduced feature sizes and line spacing while maintaining manufacturing feasibility and cost-effectiveness.
3Adaptability or versatility
If conventional PCB processes are used, then manufacturing is straightforward, but advanced components like ICs and RF antennae cannot be integrated
Solution Approach 1:
The patent creates a universal manufacturing process that can integrate multiple component types (ICs, RF antennae, passive components) directly on the PCB during the same electrochemical deposition process. The electro-less copper deposition and electroplating techniques provide a platform that simultaneously supports fine-pitch IC mounting, RF trace formation, and passive component integration, eliminating the need for separate specialized processes for each component type.
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 enables the production of high density circuit structures with reduced line and feature pitches, improving electrical performance and reliability while maintaining a low cost of manufacture, and allows for the integration of advanced components like ICs and RF antennae without the need for laser ablation, thus overcoming the limitations of traditional dry film processes.
Implementation Method 1
depositing a liquid dielectric material onto a circuit board
Implementation Method 2
electro-less copper deposition
Implementation Method 3
electroplating to form conductive structures
Data Source
AI summary
A high density region for a low density circuit. At least a first liquid dielectric layer is deposited on the first surface of a first circuitry layer. The dielectric layer is imaged to create plurality of first recesses. Surfaces of the first recesses are plated electro-lessly with a conductive material to form first conductive structures electrically coupled to, and extending generally perpendicular to, the first circuitry layer. A plating resist is applied. A conductive material is electro-plated to the first conductive structure to substantially fill the first recesses, and the plating resist is removed.