Package Substrate with Embedded Sub-Package for Noise Suppression
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Solution Overview
Problem
Existing package substrates with embedded electronic components face issues such as increased size, reliability concerns due to gaps, and poor connections, especially with high-frequency noise in power supply lines for MPUs.
Innovation Solution
A package substrate design featuring a main package without embedded components and a sub-package with embedded electronic components, where the sub-package's thickness matches the bonding material's thickness, ensuring reduced size and improved reliability through separate pad conductors for electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If electronic components are embedded in the package substrate, then the area of the package substrate can be reduced, but gaps occur between the embedded component and substrate causing reliability decrease
Solution Approach 1:
The invention divides the package substrate into two separate packages: a main package containing the MPU and a sub-package containing the decoupling capacitor. This segmentation eliminates the need to embed the capacitor within the main package substrate, thereby avoiding gap formation while still achieving compact integration. The sub-package is mounted on the second principal surface of the main package, maintaining small overall area while ensuring reliable connections through dedicated bonding interfaces.
2Volume of moving object
If electronic components are embedded in the package substrate, then size reduction can be achieved, but location deviation causes poor connection to via-hole electrodes
Solution Approach 1:
By separating the decoupling capacitor into an independent sub-package, the invention eliminates positioning accuracy issues that would arise from embedding the component directly in the main package substrate. The sub-package has its own substrate that provides a stable mounting surface with precisely positioned via-hole electrodes, ensuring reliable electrical connections without the location deviation problems associated with embedding.
3Reliability
If multiple decoupling capacitors are surface-mounted to surround the MPU, then noise suppression is improved, but the package substrate size increases
Solution Approach 1:
The invention merges the decoupling capacitor with the main package by mounting the sub-package on the second principal surface of the main package. This combining approach allows the capacitor to be integrated into the package structure rather than requiring additional surface area, achieving noise suppression functionality while maintaining compact package dimensions. The sub-package serves both as a mounting structure and as the capacitor component itself.
4Length of moving object
If the sub-package thickness is reduced to match bonding material thickness, then overall package thickness is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The invention addresses the thickness control challenge by preliminarily designing the sub-package with a thickness equal to or less than the bonding material thickness from the outset. This preliminary design approach allows for proper planning of the manufacturing process, enabling precise thickness control to be built into the fabrication steps rather than being a post-processing adjustment, thereby reducing the overall package thickness while managing precision requirements through proactive design.
Data Source
AI summary
A package substrate includes a main package body including a first principal surface on which an IC is mounted, and a second principal surface, opposed to the first principal surface, on which first bonding materials for mounting are provided. An internal circuit is provided within the main package body and connected to the first bonding materials. A sub-package is arranged on the second principal surface and includes electronic components embedded therein. A thickness direction dimension being the distance from the second principal surface to a portion of the sub-package most distant from the second principal surface, is not more than a thickness direction dimension being the distance from the second principal surface to an edge of the first bonding material at the second principal surface.