Reconstructed Package Substrates for High I/O at Lower Cost
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Solution Overview
Problem
The high cost of large single substrates used in package assemblies with high I/O counts poses a challenge, as they increase the overall cost of fabricating such assemblies.
Innovation Solution
A package assembly is constructed using a reconstructed substrate composed of multiple smaller substrate portions embedded in a molding material, with a redistribution layer (RDL) structure and semiconductor devices, eliminating the need for a large single substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a large single substrate is used to provide high I/O counts, then the I/O capacity is improved, but the substrate cost increases
Solution Approach 1:
The substrate is divided into multiple smaller substrate portions (first substrate portion, second substrate portion, etc.) that are arranged in an array pattern. Each substrate portion contains a subset of the total I/O terminals, allowing the system to achieve high I/O counts without requiring a single large expensive substrate. The segmentation enables use of smaller, more cost-effective substrate units while maintaining the required total I/O capacity.
2Quantity of substance
If a large single substrate is used to provide high I/O counts, then the I/O capacity is improved, but the manufacturing yield deteriorates
Solution Approach 1:
By segmenting the substrate into multiple smaller portions, the manufacturing process can be applied to each smaller unit independently with higher precision and better yield control. Smaller substrates are easier to manufacture with consistent quality, and defects in one portion do not necessarily compromise the entire assembly, thereby improving overall yield performance while achieving high I/O counts.
3Ease of manufacture
If multiple substrate portions are used to reduce cost, then the substrate cost is improved, but the device complexity increases
Solution Approach 1:
Multiple substrate portions are combined and mounted on a single package substrate to form an integrated assembly. The substrate portions are positioned in an array pattern and electrically connected through redistribution layers, creating a unified structure that functions as a single high I/O substrate. This merging approach achieves cost reduction through multiple smaller units while presenting a simplified integrated interface to the external world.
Solution Approach 2:
Redistribution layers (RDLs) serve as intermediary structures that facilitate electrical connections between the multiple substrate portions and the external environment. The RDLs are formed on the package substrate and provide the necessary signal routing and impedance matching, managing the complexity of interconnections between multiple substrate units while maintaining a clean external interface.
Data Source
AI summary
A package assembly includes a package substrate including a molding material layer and a plurality of substrate portions embedded in the molding material layer, a redistribution layer (RDL) structure on the package substrate, and a plurality of semiconductor devices on the RDL structure.