Semiconductor Package Core Ball Layout for Warpage and Short Prevention
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Solution Overview
Problem
Current semiconductor packages face challenges in achieving high structural stability and electrical characteristics while maintaining a small size, particularly in handling high-frequency signals, due to issues like warpage during thermal expansion and potential shorts between solder balls.
Innovation Solution
The semiconductor package design incorporates core balls with larger diameters than solder balls, strategically placed between the semiconductor chip and the package substrate to support structural stability and reduce the likelihood of shorts, while also using a redistribution substrate with specific insulating and conductive layers for improved electrical connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder balls are used to connect the redistribution substrate to the package substrate, then electrical connectivity is achieved, but structural stability deteriorates due to warpage during thermal expansion
Solution Approach 1:
The patent introduces core balls as intermediary elements between the redistribution substrate and package substrate. These core balls serve as mediators that simultaneously provide electrical connectivity and mechanical support to resist warpage during thermal expansion, resolving the contradiction between maintaining electrical connection and preserving structural stability.
Solution Approach 2:
The patent employs a composite ball structure consisting of a core ball with a larger diameter solder ball attached to it. This composite structure combines the electrical conductivity of solder with the mechanical strength of a larger core element, enabling both electrical connectivity and structural stability to be achieved simultaneously.
2Stability of the object's composition
If larger diameter core balls are used to improve structural stability, then resistance to warpage increases, but the package size increases
Solution Approach 1:
The patent applies local quality by positioning core balls with larger diameters specifically at corner locations of the package substrate where warpage stress is highest, while using smaller solder balls in other areas. This localized approach provides structural stability where most needed without unnecessarily increasing overall package size.
Solution Approach 2:
The patent uses a hybrid approach where only certain critical locations (corners) employ the larger core ball structure, while other locations use standard smaller solder balls. This partial application of the larger ball design provides sufficient structural support without the excessive size increase that would result from uniformly applying large balls across the entire package.
3Reliability
If multiple layers of solder balls are used to ensure electrical connectivity, then reliability improves, but the likelihood of shorts between solder balls increases
Solution Approach 1:
The core balls serve as intermediary elements that are strategically positioned to provide electrical connectivity while maintaining larger spacing between connection points. This intermediary structure reduces the density of solder balls needed, thereby decreasing the probability of shorts while preserving reliable electrical connections.
4Device complexity
If the package substrate and semiconductor chip are directly connected, then device complexity is reduced, but structural stability during thermal expansion deteriorates
Solution Approach 1:
The patent introduces the redistribution substrate with core balls as an intermediary layer between the package substrate and semiconductor chip. This intermediary structure provides mechanical support and stress distribution during thermal expansion, enhancing structural stability while maintaining relatively simple overall device architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances structural stability and electrical characteristics, reduces the likelihood of shorts, and allows for a smaller package size by supporting the semiconductor chip and package substrate during thermal expansion and improving electrical connectivity through the redistribution substrate.
Implementation Method 1
The redistribution substrate may be electrically connected to the package substrate through a plurality of solder balls on a bottom surface of the redistribution substrate. The at least one core ball may be electrically connected to the redistribution substrate.
Implementation Method 2
Current semiconductor packages face challenges in achieving high structural stability and electrical characteristics while maintaining a small size, particularly in handling high-frequency signals, due to issues like warpage during thermal expansion
Data Source
AI summary
A semiconductor package includes a package substrate, substrate pads provided on a top surface of the package substrate, at least one core ball on at least one of the substrate pads, a redistribution substrate provided on the top surface of the package substrate, and a semiconductor chip mounted on the redistribution substrate. The redistribution substrate is electrically connected to the package substrate through a plurality of solder balls provided on a bottom surface of the redistribution substrate. The at least one core ball is electrically connected to the redistribution substrate. A diameter of the at least one core ball is greater than a diameter of each of the plurality of solder balls.