Cavity-Embedded PCB for Thick Semiconductor Mounting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge is to reduce the overall thickness of printed circuit boards, particularly when mounting relatively thick semiconductor chips, as the slimming of prepreg insulation layers has reached a limit, and existing methods are insufficient for achieving the necessary miniaturization in mobile devices.
Innovation Solution
A printed circuit board design that includes a core substrate, a first insulation layer, a via with a pad on its surface, a form maintenance prepreg layer with a cavity, and a second insulation layer, where the cavity exposes the top surface of the first insulation layer and via, along with a protection layer to prevent oxidation and contamination, allowing for the mounting of thick semiconductor chips within the cavity to reduce the board's thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of prepreg insulation layers is reduced to achieve thinner PCBs, then the overall thickness of the printed circuit board is reduced, but the slimming reaches a limit and cannot achieve further miniaturization
Solution Approach 1:
The patent introduces a cavity structure that creates a localized three-dimensional space within the PCB layer. This cavity allows semiconductor chips to be mounted in a recessed area rather than on a flat surface, effectively utilizing vertical space to reduce the overall board thickness without requiring further reduction of insulation layer thickness.
Solution Approach 2:
The semiconductor chip is nested within the cavity formed in the PCB structure. The cavity acts as a container that houses the chip, allowing the chip thickness to be accommodated within the board's overall thickness envelope rather than adding to it externally.
2Reliability
If thicker semiconductor chips are mounted on conventional rigid PCBs, then the functionality and performance are improved, but the overall thickness of the final product increases
Solution Approach 1:
By creating a cavity that transitions the mounting surface from two-dimensional (flat PCB surface) to three-dimensional (recessed cavity space), the patent allows thick chips to be accommodated within the board thickness rather than extending beyond it, thus maintaining performance while reducing overall profile.
Solution Approach 2:
The cavity structure serves as an intermediary element between the thick semiconductor chip and the PCB surface. This intermediate structure absorbs the thickness difference, allowing the chip to be mounted at a lower profile while maintaining electrical and mechanical connections.
3Reliability
If additional protection layers and solder resist are applied to protect exposed via surfaces, then the reliability and protection are improved, but the manufacturing process complexity and time increase
Solution Approach 1:
The patent combines the cavity formation process with the via protection strategy. The cavity walls themselves serve as protective structures for the vias, eliminating the need for separate protection layers. Additionally, the same insulation layer materials used in cavity formation can serve dual purposes of structural support and via protection.
Solution Approach 2:
The insulation layers and cavity structure serve multiple functions simultaneously: they provide electrical insulation, structural support, and protection for exposed via surfaces. This multi-functionality eliminates the need for dedicated protection layers, simplifying the manufacturing process.
Data Source
AI summary
The object of the present invention is to provide a printed circuit board formed with a cavity to mount a semiconductor chip.