PCB Via Formation Using Photolithography for High Density
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Solution Overview
Problem
The challenge in manufacturing printed circuit boards lies in achieving high circuit density and reducing via sizes to form interlayer connections while maintaining cost-effectiveness, as existing methods struggle to efficiently produce fine circuits and reduce via sizes.
Innovation Solution
The solution involves a printed circuit board design with a core board, insulating layers, and vias that connect circuit layers on both surfaces, utilizing a photosensitive resin layer that extends through the core board to form hourglass-shaped vias, and a manufacturing method that includes photolithography to create smaller via holes, allowing for high-density circuit formation and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to manufacture fine circuits and reduce via sizes, then via sizes can be reduced, but manufacturing cost increases and productivity decreases
Solution Approach 1:
The patent merges the formation of multiple via holes into a single photolithography process step, allowing simultaneous creation of multiple vias with different sizes and positions. This combines what would traditionally require separate drilling and plating operations into one integrated process, achieving both fine via sizes and cost reduction through process consolidation.
Solution Approach 2:
The patent changes the fundamental parameter of via formation from mechanical drilling to photolithographic patterning. By using light-based processes instead of mechanical removal, the system achieves precise control over via size and shape while enabling parallel fabrication of multiple vias, thereby improving both precision and productivity simultaneously.
2Quantity of substance
If via sizes are reduced to form high density interlayer connections, then circuit density increases, but manufacturing complexity increases
Solution Approach 1:
The patent replaces the mechanical drilling system with a photolithographic system for via formation. This substitution eliminates the need for mechanical drill bits and associated tooling, allowing complex via patterns to be created through light exposure without increasing mechanical manufacturing complexity. The optical process inherently handles high density patterns more easily than mechanical methods.
Solution Approach 2:
The patent introduces a new dimension of control by using photomask patterns to define via positions and sizes. Instead of controlling via formation through mechanical tool paths in three-dimensional space, the system uses two-dimensional photomask patterns that are projected onto the substrate, adding a pattern dimension that simplifies the control of complex via arrangements.
3Productivity
If multiple via holes are formed simultaneously using photolithography, then productivity increases, but via size reduction becomes more difficult
Solution Approach 1:
The patent applies local quality by using different photomask patterns for different regions of the substrate. Each region can have its own optimized via size and pattern, allowing simultaneous fabrication of various via types (different sizes, positions, and densities) in a single process run. This regional customization maintains precision while achieving high productivity through parallel processing.
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 printed circuit boards with fine patterns and high-density circuits, reducing via sizes and manufacturing costs by using photolithography to form multiple via holes simultaneously, thereby improving circuit density and efficiency.
Implementation Method 1
The insulating layer may be a photosensitive resin layer
Data Source
AI summary
A printed circuit board and a method of manufacturing the same are provided. The printed circuit board includes an insulating layer including a first resin layer and a second resin layer, circuit layers disposed on upper and lower surfaces of the insulating layer, and a via configured to connect the circuit layer formed on the upper surface to the circuit layer formed on the lower surface, and the second resin layer extends from an upper surface of the first resin layer to a lower surface of the first resin layer by passing through the first resin layer as to contact a side surface of the via.