Resin Substrate Warpage Reduction via Local Quality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional resin substrates with uneven conductor pattern density across layers are prone to warpage during thermal processes like reflow, leading to mounting failures, especially in elongated shapes with external connection conductors at both ends.
Innovation Solution
A resin substrate design with alternating portions of varying conductor pattern density and interlayer connection conductor diameters, where the first portion has a lower conductor pattern density and larger interlayer connection conductor diameters compared to the second portion, reducing the density difference and minimizing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductor pattern density is increased on the reverse surface to achieve higher electrical connectivity, then the electrical connection reliability is improved, but the warpage of the resin substrate increases due to thermal stress during reflow
Solution Approach 1:
The patent applies local quality by varying the conductor pattern density in different regions of the substrate. Specifically, the reverse surface is divided into a first region with higher conductor pattern density and a second region with lower conductor pattern density, allowing different areas to serve different functional requirements while balancing overall thermal stress distribution
Solution Approach 2:
The patent changes the density parameter of conductor patterns across different regions of the substrate. By adjusting the conductor pattern density from the first region to the second region, the patent optimizes both electrical connectivity and thermal stress distribution to prevent warpage
2Adaptability or versatility
If the external connection conductors are provided at both ends of an elongated substrate to enhance connectivity, then the electrical functionality is improved, but the mounting failure rate increases due to warpage-induced misalignment
Solution Approach 1:
The patent applies local quality by creating distinct regions with different conductor pattern densities. The first region near the external connection conductors has higher density to ensure electrical connectivity, while the second region has lower density to reduce thermal stress and prevent warpage that would cause mounting misalignment
Solution Approach 2:
The patent applies preliminary anti-action by pre-balancing the conductor pattern density distribution across the substrate before the reflow process. This preemptive design compensates for thermal stress effects, preventing warpage-induced mounting failures before they occur
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 warpage due to thermal history, ensuring reliable surface mounting on printed wiring boards by balancing conductor pattern density and interlayer connection conductor sizes across the substrate.
Implementation Method 1
by a thermal history at the time of reflow during surface mounting or the like, the front surface 11 of the resin substrate 10P shrinks and warps
Data Source
AI summary
A resin substrate includes a first portion including a plurality of resin sheets provided at one end in a stacking direction and a second portion including a plurality of resin sheets provided at the other end in the stacking direction. The thickness of the plurality of resin sheets is the same or substantially the same as the thickness of the first portion and the second portion. The density of planar conductor patterns of the first portion with respect to the volume of the first portion is lower than the density of planar conductor patterns of the second portion with respect to the volume of the second portion. The average of the diameters of the first interlayer connection conductor provided in the first portion is greater than the average of the diameters of the second interlayer connection conductor provided in the second portion.