Multilayer Board With Gradient Melting Points For Uniform Lamination
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Solution Overview
Problem
The existing manufacturing methods for multilayer boards using liquid crystal polymer substrates often result in uneven heating during thermal pressing, leading to poorly pressed boards due to the differences in distance from the heat source among dielectric layers.
Innovation Solution
A multilayer board design where the liquid crystal polymer substrates have varying melting points, with the middle substrates having the lowest melting points and the outermost substrates having the highest, ensuring that all substrates deform similarly during hot pressing, thereby achieving uniformity and preventing poor lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional thermal pressing is applied to multilayer boards with liquid crystal polymer substrates, then the pressing process can be completed, but uneven heating occurs due to different distances from the heat source, resulting in poor lamination quality
Solution Approach 1:
The patent applies local quality by assigning different melting points to liquid crystal polymer substrates at different positions within the multilayer board. Specifically, substrates closer to the heat source have higher melting points while those farther away have lower melting points, allowing each local region to be pressed at its optimal temperature despite the temperature gradient during thermal pressing
Solution Approach 2:
The patent changes the physical parameter of melting point across different liquid crystal polymer substrates based on their position in the stack. By selecting substrates with progressively different melting points from top to bottom (or vice versa), the pressing process can achieve uniform lamination quality across all layers despite the inherent temperature gradient caused by distance from the heat source
2Ease of manufacture
If liquid crystal polymer substrates with the same melting point are used, then material selection is simplified, but uneven deformation occurs during hot pressing leading to poor flatness
Solution Approach 1:
Different liquid crystal polymer substrates are selected for different positions in the multilayer board based on their melting points. Substrates nearer to the heat source (which experience higher temperatures) have higher melting points, while those farther away have lower melting points, ensuring uniform deformation and flatness across all layers
Solution Approach 2:
The patent introduces asymmetry in material properties (melting points) to compensate for the asymmetric temperature distribution during pressing. Rather than using identical symmetric materials, the melting points are deliberately varied to match the asymmetric thermal environment, achieving symmetric deformation behavior and uniform flatness
3Ease of operation
If uniform temperature is applied during thermal pressing, then the pressing process is simple to control, but substrates at different distances from the heat source experience uneven heating and deformation
Solution Approach 1:
The patent changes the material parameter (melting point) of liquid crystal polymer substrates to compensate for the temperature gradient. By selecting substrates with melting points that increase toward the heat source, the material properties adapt to the thermal environment, allowing simple uniform temperature control to produce high-quality lamination
Solution Approach 2:
The patent converts the harmful effect of temperature gradient (which causes uneven heating) into a beneficial effect by matching substrate melting points to position. The temperature difference that would normally cause poor lamination is instead utilized to achieve uniform pressing by having outer substrates (closer to heat source) with higher melting points and inner substrates with lower melting 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
The use of substrates with different melting points ensures that the multilayer board is pressed uniformly, resulting in improved flatness, yield, and electrical performance of the board.
Implementation Method 1
Each of the liquid crystal polymer substrates has a melting point. When a number of the liquid crystal polymer substrates is an odd number equal to or higher than 3, the liquid crystal polymer substrates include a first middle substrate that is located in the most middle position, a first melting point of the first middle substrate is lowest among the melting points of the liquid crystal polymer substrates
Implementation Method 2
the melting point of the liquid crystal polymer substrate closest to the heat sources is Tm, and a temperature of the heat sources is Tm−30° C. to Tm° C.
Data Source
AI summary
A multilayer board includes laminates. Each of the laminates includes a liquid crystal polymer substrate and a metal layer. Each of the liquid crystal polymer substrates has a melting point. The number of the liquid crystal polymer substrates is an even number, they include first and second middle substrates that are located in the most middle position and respectively have first and second melting points that are substantially same. The first or second melting point is lowest among the melting points. The melting points increase in a direction away from the first and second middle substrates.