Multilayer Wiring Board Lamination via Segmented Non-Through Holes
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Solution Overview
Problem
Existing methods for manufacturing multilayer wiring boards face challenges in achieving high-density connections with small pitches and large board thickness, particularly in forming small-diameter holes and ensuring accurate alignment and reliable electrical connections, due to issues such as drill breaking, uneven thickness, and void formation during the interlayer connection process.
Innovation Solution
A method involving the lamination of printed wiring boards with insulating films containing through holes, filled with a conductive material, and using alignment pins for precise alignment, which allows for the formation of small-pitch, high-density connections without the need for through-holes, thereby enhancing connection reliability and board thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through holes are formed in large and thick multilayer wiring boards to establish electrical connections, then electrical connection is achieved, but the aspect ratio increases making drill breaking and alignment accuracy difficult
Solution Approach 1:
The patent divides the single through-hole structure into multiple non-through holes (first non-through holes in lower insulating layer, second non-through holes in upper insulating layer) that do not pass through the entire board thickness. This segmentation reduces the aspect ratio of each hole, preventing drill breaking and improving alignment accuracy while maintaining electrical connection reliability through multiple distributed connection points.
Solution Approach 2:
The patent transitions from a vertical through-hole structure (one dimension) to a distributed non-through hole structure across multiple layers (adding layer dimension). By forming holes only in specific insulating layers rather than through the entire board, the solution addresses the aspect ratio problem by changing the dimensional approach to hole formation.
2Productivity
If smaller-diameter holes are bored to achieve smaller pitches and higher density, then component mounting density increases, but drill breaking risk and alignment difficulty increase
Solution Approach 1:
The patent segments the hole formation process into separate non-through holes in different insulating layers, allowing smaller diameters without through-hole constraints. This enables smaller pitches and higher component mounting density while reducing drill breaking risk since each hole only penetrates part of the board thickness rather than requiring precise through-hole alignment.
3Manufacturing precision
If non-through holes are used for interlayer connection to reduce aspect ratio, then alignment accuracy improves, but connection reliability between multiple layers may be compromised
Solution Approach 1:
The patent combines multiple non-through holes (first non-through holes and second non-through holes) across different insulating layers to create a distributed connection system. This merging of multiple connection points compensates for the non-through structure, ensuring reliable electrical connection between multiple layers while maintaining the alignment accuracy benefits of reduced aspect ratio.
Solution Approach 2:
The patent uses the layer dimension to distribute connection points across multiple insulating layers rather than relying on a single through-hole path. This multi-layer non-through hole approach maintains alignment accuracy while achieving reliable interlayer connection through distributed connection points.
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 fabrication of high-density multilayer wiring boards with excellent connection reliability, small-diameter holes, and minute junction terminal pitches, overcoming the limitations of existing technologies by ensuring accurate alignment and stable electrical connections.
Implementation Method 1
filled with a conductive material... to establish a connection between the plurality of printed wiring boards through the conductive paste
Implementation Method 2
using alignment pins for precise alignment
Implementation Method 3
lamination step (II) of overlaying the plurality of printed wiring boards so that the electrical connection pads face each other, and laminating the plurality of printed wiring boards
Data Source
AI summary
A method for manufacturing a multilayer wiring board is disclosed. The Method comprises a step (I) of preparing printed wiring boards having both electrical connection pads for establishing an electrical connection between the boards and non-connection pads for not establishing an electrical connection between the boards on the same plane; and a lamination step (II) of overlaying the boards so that the electrical connection pads face each other, and laminating the boards so that the boards are bonded to each other through a conductive material provided between the facing electrical connection pads. In the step (I), to at least one of surfaces faced when the boards are overlaid in the step (II), an insulating film having through holes formed in positions corresponding to the electrical connection pads on the surface is attached (Ia), and the conductive material is provided in the through holes (Ib).