Fan-out Package Interface Leveling for Encapsulant Bleeding
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Solution Overview
Problem
Fan-out semiconductor packages face defects due to encapsulant bleeding and reduced via reliability, which affect the miniaturization and reliability of semiconductor chips.
Innovation Solution
The interface between the second connection member and the encapsulant is positioned at a different level than the interface between the second connection member and the redistribution layer or the connection pad, with step heights in the redistribution layer and connection pad surfaces to prevent encapsulant bleeding and ensure sufficient via volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulant is applied to encapsulate the semiconductor chip and connection members, then the semiconductor chip is protected and integrated, but the encapsulant may bleed toward the connection pad causing defects
Solution Approach 1:
A barrier structure is formed on the connection pad before the encapsulant is applied. This barrier structure prevents the encapsulant from bleeding onto the connection pad during the encapsulation process, thereby eliminating the defect while maintaining proper encapsulation protection.
Solution Approach 2:
The barrier structure acts as an intermediary layer between the encapsulant and the connection pad. It mediates the interaction by providing a physical boundary that prevents the encapsulant from directly contacting and bleeding onto the connection pad, thus solving the bleeding issue.
2Volume of moving object
If the via size is reduced to enable miniaturization, then the package size is reduced, but the via reliability is compromised
Solution Approach 1:
The barrier structure is selectively formed only in the region surrounding the connection pad, not throughout the entire device. This localized approach prevents encapsulant bleeding at the critical interface while maintaining via reliability and allowing miniaturization in other areas of the package.
Solution Approach 2:
The barrier structure is prepared in advance to counteract the potential harmful effect of encapsulant bleeding. By having this protective structure in place before encapsulation, the design preemptively prevents the bleeding defect without compromising via integrity or requiring larger via dimensions.
Data Source
AI summary
A fan-out semiconductor package includes a first connection member having a through hole, a semiconductor chip in the through hole, having an active surface with a connection pad and an inactive surface on an opposing side. An encapsulant encapsulates at least a portion of the first connection member and the semiconductor chip. A second connection member is on the first connection member and the semiconductor chip. The first connection member and the second connection member each include a redistribution layer electrically connected to a connection pad of the semiconductor chip. The interface between the second connection member and the encapsulant is located on a different level from the level of the interface between the second connection member and a redistribution layer of the first connection member or the level of the interface between the second connection member and a connection pad of the semiconductor chip.