Embedded Bump Pad PCB for Package-on-Package Thickness
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Solution Overview
Problem
In package-on-package (POP) structures, the reduction in solder ball height limits the thickness of electronic elements mounted on lower packages, making it difficult to achieve the desired thickness due to decreased pitch and height of solder balls.
Innovation Solution
A printed circuit board design featuring an insulating material with embedded bump pads, stacked insulating layers, and bumps that protrude into cavities, allowing for increased electronic element thickness without exceeding predetermined dimensions, and enabling efficient bonding through conductive members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the pitch and height of solder balls are decreased to enable finer circuits on lower packages, then the circuit density is improved, but the thickness of electronic elements mounted on the lower package cannot be increased to the required thickness
Solution Approach 1:
The patent introduces an interposer board as an intermediary component between the lower package and upper package. This interposer board with its own substrate and circuit patterns allows the electronic element on the lower package to be mounted with adequate thickness requirements while maintaining the fine pitch solder ball connections. The interposer acts as a mediator that decouples the thickness constraint from the circuit fineness requirement.
Solution Approach 2:
The patent adds a vertical dimension by stacking multiple packages and an interposer board in layers. Instead of trying to increase thickness within the same plane, the solution moves to three-dimensional stacking, where the electronic element thickness is satisfied in the vertical direction through layered construction of lower package, interposer board, and upper package.
2Length of moving object
If the height of solder balls is decreased, then the pitch between packages is reduced, but the electronic element thickness requirement cannot be met
Solution Approach 1:
The interposer board serves as a mediator that allows maintaining small package pitch while satisfying electronic element thickness. The interposer board absorbs part of the vertical space, enabling the electronic element to achieve required thickness without increasing the overall package-to-package distance.
Solution Approach 2:
The patent segments the overall package structure into multiple independent layers: lower package, interposer board, and upper package. This segmentation allows each layer to be optimized independently - the lower package and upper package can maintain close pitch while the interposer board provides the necessary vertical space for electronic element thickness.
3Length of stationary object
If a separate interposer is used to increase electronic element thickness, then the thickness requirement is satisfied, but the device complexity increases
Solution Approach 1:
The interposer board is designed with multi-functionality: it serves as a mechanical support structure, provides electrical interconnection between packages, and enables the electronic element to achieve required thickness. By combining multiple functions into a single component, the overall device complexity is minimized while still satisfying the thickness requirement.
Solution Approach 2:
The patent merges the interposer board with the package structure, integrating it as an essential part of the stacked configuration. Rather than being a separate add-on component, the interposer board is combined with the lower and upper packages to form a unified multi-layer structure, reducing the number of discrete components and simplifying the overall device architecture.
Data Source
AI summary
A printed circuit board including: an insulating material having a bump pad embedded in a first surface thereof; a first insulating layer stacked on the first surface of the insulating material and including an opening portion exposing the bump pad; a second insulating layer stacked on the first insulating layer and including a first cavity exposing the opening portion; and a bump disposed on the bump pad in the opening portion.