Adhesive-Free Multilayer Circuit Board With Conductive Paste
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Solution Overview
Problem
Multilayer printed circuit boards face issues with adhesive layers being non-essential materials, leading to unsatisfactory electric characteristics and high production costs, while build-up multilayer wiring boards have lengthy manufacturing processes and high costs due to the yield being affected by the number of layers.
Innovation Solution
A circuit board is manufactured by alternately laminating first and second insulating base materials without adhesive layers, with patterned metal layers and conductive paste-filled through holes to connect them, allowing for a trapezoidal shape configuration that enhances electrical connectivity and reduces production time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesive layers are used to join multiple substrates, then the substrates can be connected, but the electric characteristics deteriorate and production cost increases
Solution Approach 1:
The patent removes adhesive layers from the multilayer circuit board structure entirely. Instead of using adhesive layers to join substrates, the invention uses through holes filled with conductive paste to create direct electrical connections between metal layers on adjacent substrates, eliminating the adhesive layer component from the system.
Solution Approach 2:
The patent introduces through holes filled with conductive paste as an intermediary connection method between substrates. These through holes act as mediators that provide both mechanical support and electrical connectivity without requiring adhesive layers, solving the contradiction between connection needs and electric characteristics.
2Productivity
If adhesive layers are used to join multiple substrates, then the substrates can be connected, but production time increases and cost increases
Solution Approach 1:
The patent eliminates adhesive layers from the manufacturing process, removing the associated application, drying, and curing steps. This extraction of the adhesive layer component directly reduces production time and associated costs while maintaining substrate connection functionality through alternative means.
Solution Approach 2:
The patent incorporates through holes and conductive paste during the substrate preparation phase rather than adding them as separate post-assembly steps. This preliminary integration of connection structures into the substrate manufacturing process reduces overall production time and eliminates the need for separate adhesive application steps.
3Ease of manufacture
If build-up multilayer wiring boards are manufactured by laminating multiple layers, then the circuit board can be formed, but the manufacturing process takes a very long time and yield decreases
Solution Approach 1:
The patent divides the multilayer circuit board into separate substrate units, each with pre-formed through holes and conductive paste connections. These segmented units can be manufactured independently and then assembled, reducing the complexity and time of the overall manufacturing process while improving yield by isolating defects to individual units.
Solution Approach 2:
The patent performs the formation of through holes and conductive paste filling during the substrate manufacturing phase rather than during the final assembly phase. This preliminary action eliminates time-consuming steps from the post-assembly process and reduces the cumulative effect of yield losses across multiple lamination steps.
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 method enables the production of multilayer circuit boards with improved electric characteristics, shortened manufacturing processes, and reduced costs by eliminating adhesive layers and optimizing the lamination of unit components.
Implementation Method 1
a first conductive paste filling a through hole of the first insulating base material so as to connect the first metal layer and the second metal layer
Implementation Method 2
multiple insulating base materials that are formed with wiring patterns are joined to one another by adhesive layers
Data Source
AI summary
A circuit board includes a plurality of first insulating base materials and a plurality of second insulating base materials that are alternately laminated, a first metal layer being formed into a pattern shape on a first surface of the first insulating base material, and a second metal layer being formed into a pattern shape on a second surface of the first insulating base material. The first metal layer is formed into a trapezoidal shape that is large in diameter on a first surface side of the first insulating base material. The second metal layer is formed into a trapezoidal shape that is large in diameter on a second surface side of the first insulating base material. The first metal layers and the second metal layers are laminated in such a manner that the trapezoidal shapes are alternately oriented.