Semiconductor Package Metal Pattern for Underfill Isolation
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Solution Overview
Problem
Contamination of solder balls in semiconductor packages by underfill can degrade the performance and reliability of the package.
Innovation Solution
A semiconductor package design featuring a redistribution substrate with a metal pattern between the silicon capacitor and solder balls, where the metal pattern is positioned to prevent underfill from contacting the solder balls, thereby maintaining the integrity of the solder balls and enhancing package reliability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If underfill is applied between the silicon capacitor and redistribution substrate, then the mechanical strength and reliability of the connection is improved, but the solder balls may be contaminated by the underfill
Solution Approach 1:
A metal pattern is introduced as an intermediary element between the underfill and the solder balls. The metal pattern extends from the ball pad toward the silicon capacitor and is positioned to intercept the underfill before it can reach the solder balls. This intermediary structure allows the underfill to be applied for mechanical strength while preventing it from contaminating the solder balls, thus resolving the technical contradiction.
2Object-affected harmful factors
If the metal pattern is positioned close to the silicon capacitor to block underfill, then solder ball contamination is prevented, but the metal pattern may interfere with the capacitor structure
Solution Approach 1:
The metal pattern is designed with local quality by extending only in specific regions where underfill flow is problematic. The pattern starts from the ball pad and extends partially toward the silicon capacitor, covering only the areas where underfill interception is needed, while leaving other areas clear to avoid interference with the capacitor structure. This localized approach prevents contamination without creating device complexity.
3Object-affected harmful factors
If the metal pattern extends far toward the silicon capacitor, then underfill contamination is better prevented, but the manufacturing precision required increases
Solution Approach 1:
The metal pattern is designed to extend from the ball pad toward the silicon capacitor in a predetermined manner, with its position and extent optimized to intercept underfill flow before reaching the solder balls. By establishing the metal pattern's position in advance during the manufacturing process, the design achieves effective contamination prevention while maintaining reasonable manufacturing precision requirements.
Data Source
AI summary
A semiconductor package includes a redistribution substrate having a first side and an opposite second side, a semiconductor chip on the first side of the redistribution substrate, a silicon capacitor on the second side of the redistribution substrate, a plurality of solder balls on the second side of the redistribution substrate and adjacent the silicon capacitor, and a metal pattern in the redistribution substrate and positioned between the silicon capacitor and the solder balls. The metal pattern includes a first portion extending in a first direction, and a second portion connected to the first portion and extending in a second direction different from the first direction.