Multilayer Board Conductor Stability via Segmented Line Width
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Solution Overview
Problem
During thermocompression bonding of multilayer boards made of thermoplastic resin, linear conductors tend to tilt, leading to potential short circuits due to contact between adjacent conductors, and increasing line width to prevent tilting results in decreased wiring density.
Innovation Solution
Forming linear conductors with a combination of wide and narrow portions on each base material layer, where the wide portions overlap the narrow portions and their end portions, increasing the resistance of the thermoplastic resin and preventing tilting without reducing wiring density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the line width of each linear conductor is increased to prevent tilting, then the tilting is reduced, but the wiring density decreases
Solution Approach 1:
The patent applies local quality by creating different line width portions (wide and narrow) within the same conductor pattern. The wide portion provides stability to prevent tilting during thermocompression bonding, while the narrow portion maintains high wiring density. This local variation in line width allows different sections of the conductor to serve different functional purposes within the same overall structure.
Solution Approach 2:
The patent resolves the contradiction by transitioning from a one-dimensional solution (uniform line width) to a two-dimensional solution (varying line width across different portions). By utilizing the planar dimension to create wide and narrow sections, the patent achieves both stability (through wide portions) and high wiring density (through narrow portions) without requiring increased conductor thickness or other dimensional compromises.
2Reliability
If the line width is increased to prevent conductor tilting, then the conductors remain stable, but the center interval must be increased reducing wiring density
Solution Approach 1:
The patent applies local quality by creating different line width portions (wide and narrow) within the same conductor pattern. The wide portion provides stability to prevent tilting during thermocompression bonding, while the narrow portion maintains high wiring density. This local variation in line width allows different sections of the conductor to serve different functional purposes within the same overall structure.
Solution Approach 2:
The patent segments the conductor line width into distinct wide and narrow portions. The wide portion is specifically designed to prevent tilting during bonding, while the narrow portion allows for closer spacing of adjacent conductors. This segmentation enables the conductor to simultaneously achieve positioning accuracy and maintain high wiring density.
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
Significantly reduces or prevents tilting of linear conductors in the stacking direction during thermocompression bonding, maintaining wiring density and preventing short circuits, even with multiple layers, and allows for the use of the multilayer board as an electromagnet.
Implementation Method 1
when a plurality of base material layers made of a thermoplastic resin are stacked and thermocompression bonding is performed, the thermoplastic resin flows during the thermocompression bonding
Implementation Method 2
the thermoplastic resin flows during the thermocompression bonding
Implementation Method 3
the resistance of the fluid thermoplastic resin increases, and thus tilting of the wide portions in the stacking direction is significantly reduced or prevented
Data Source
AI summary
In a linear conductor forming step, a wide portion having a relatively large line width and a narrow portion having a relatively small line width are formed in each of a plurality of linear conductors. In addition, in a multilayer board, in base material layers adjacent to each other in a stacking direction, the wide portion overlaps the narrow portion on the adjacent base material layer, and end portions of the wide portions at both sides of the narrow portion in a line width direction, in a planar view. The wide portions are disposed such that the end portions thereof overlap each other in the stacking direction and resistance of a fluid thermoplastic resin increases. The narrow portion is located between the wide portions in the stacking direction.