Bottom Package Routing Paths for High Bandwidth Die-on-Package
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional package-on-package (PoP) structures face challenges with increased memory bandwidth requirements due to limitations in the number of electrical connections between the top and bottom packages, primarily caused by the size and pitch of solder balls, which affect reliability and lead to electrical shorts.
Innovation Solution
A high bandwidth bottom package is developed using a substrate with a dielectric material and conductive pads, where a layer of dielectric material covers the integrated circuit die and pads, and holes are filled with conductive material to create finer pitch connections, enabling more electrical connections without the need for additional substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder balls are used to couple the bottom package to the top package, then electrical connections are provided, but the pitch between solder balls must increase to meet clearance requirements, reducing the number of connections
Solution Approach 1:
The patent changes the material parameter from conventional solder balls to copper cored solder balls, which have different mechanical properties (not susceptible to collapse). This parameter change allows reduction of the pitch between connection points while maintaining reliability, thereby increasing the number of connections from two rows to three rows
Solution Approach 2:
The patent adds a third row of pads and copper cored solder balls in the vertical dimension, transitioning from a two-row configuration to a three-row configuration. This dimensional expansion increases the number of connections between the bottom package and top package while maintaining acceptable pitch dimensions
2Quantity of substance
If the pitch between solder balls is reduced to increase connections, then the number of connections increases, but solder ball collapse occurs reducing reliability
Solution Approach 1:
The patent uses composite material structure - copper cored solder balls consisting of a copper core surrounded by a solder outer layer. The copper core provides structural support preventing collapse, while the solder outer layer provides electrical conductivity and bonding capability. This composite structure enables reduced pitch while maintaining reliability
3Reliability
If two rows of solder balls are used to meet clearance requirements, then reliability is maintained, but the number of connections is insufficient for high bandwidth requirements
Solution Approach 1:
The patent changes the material parameter from conventional solder balls to copper cored solder balls, enabling pitch reduction and adding a third row of connections. This increases the total number of connections available for data transmission, thereby increasing memory bandwidth while maintaining the two-row clearance structure for reliability
Solution Approach 2:
The patent expands the connection configuration from two rows to three rows by adding connections in the vertical dimension. This dimensional expansion provides additional signal paths for increasing memory bandwidth while maintaining the original two-row clearance structure
Data Source
AI summary
A system, method, and computer program product are provided for producing a high bandwidth bottom package of a die-on-package structure. The method includes the steps of receiving a bottom package comprising a substrate material having a top layer and an integrated circuit die that is coupled to the top layer of the substrate material. A first set of pads is formed on the top layer of the substrate material and a layer of dielectric material is applied on a top surface of the bottom package to cover the integrated circuit die and the first set of pads.